and
toexplicitlymarkparagraphs.(Inthepreviousmethod,wehadjustusedCarriageReturnsandLineFeedstomarkthem.)Wemaywrite:Thisisthefirst,whichisimportant.
Inthetypesettinglanguageusedforwritingthisbook,mark-upisintroducedwiththebackslashescapecharacter,followedbyadescriptivenameofthechangebeingmade,withthecontentsenclosedincurlybrackets{and}:\section{SectionTitle}Thisisthe\textit{first}paragraph,whichis\textbf{important}.Here,wehaveused\section{}forthesectiontitle,\textit{}foritalic,and\textbf{}forbold.Thesedifferingmark-upsystemsarenotjusthistoricalartefacts:theyservedifferentpurposes.Therequirementsmaybewhollydifferentforadocumenttobeprinted,tobeputontheweb,ortobeviewedonaneBookreader.Wepromisedtotalkaboutrepresentingtheworld’smanylan-guagesandwritingsystems.Since1989,therehasbeenaninter-nationalindustrialeffort,undertheUnicodeinitiative,toencodemorethanonehundredthousandcharacters,givingeachanumber,anddefininghowtheymaybecombinedinvalidways.Therearemorethanamilliontotalslotsavailableforfutureuse.ItisimportanttosaythattheUnicodesystemisconcernedonlywithassigningcharacterstonumbers.Itdoesnotspecifytheshapesthosecharacterstake:thatisamatterfortypefacedesigners.Theprincipleisoneofseparationofconcerns:thateachpartofacom-putersystemshoulddoonejobwellandallowinteractionwiththeother,similarlywell-designedcomponents.ThisisparticularlydifficultfortheUnicodesystem,whichmustnavigateinnumerableculturaldifferencesandawidevarietyofpossibleuses.ThefollowingfivepagesgivesomeexamplesdrawnfromthehugeUnicodestandard. #################### File: A%20MACHINE%20MADE%20THIS%20BOOK%20ten%20sketches%20of%20computer%20science%20-%20JOHN%20WHITINGTON%20%28PDF%29.pdf Page: 150 Context: # Chapter 10. Words to Paragraphs What do we notice? The left and right hands of the block of text are straight—no ragged edges. This is called full justification. We notice that some of the lines have a hyphen at the end, in the middle of a word. Looking carefully, we see that the spacing between words is not consistent from line to line. The last line of each paragraph does not go all the way to the end; the first may be indented. How do we build a line from a list of letters? We know that each letter in a typeface has an origin, as well as an advancement which specifies how far to move to the right after drawing a character. We know also about kerning, which tells us that certain letter combinations must appear closer together. Here is a line of text, showing the (usually invisible) boxes which help to position each character: > “What’s happened to me”, he thought. > What’s happened to me, he thought. If all our characters fortuitously added up to the correct width for a line, or we were happy to break words with hyphens anywhere, or did not want a straight right edge, this is all we would have to do. We would draw the characters in order until we reached the end of a line, and then start on the next line, moving down the page the right amount (called the leading—pronounced “ledding”). Alas, the world is not that simple, and we must add space to fill out the line. This can look poor if done badly, especially when a narrow column is used, such as in a newspaper: | Full justification in a narrow column can make big gaps between words and letters. | Here, space has been added not only between words but between letters, to make the line fit. Generally, we like to add most of the needed space between words, rather than between individual letters. Here is a paragraph typeset to three different column widths: #################### File: A%20MACHINE%20MADE%20THIS%20BOOK%20ten%20sketches%20of%20computer%20science%20-%20JOHN%20WHITINGTON%20%28PDF%29.pdf Page: 93 Context: # Chapter 6. Saving Space ## 79 | Character | Decimal | Binary | |-----------|---------|---------| | a | 4 | 0010 | 01001 | | f | 4 | 0000 | 0101000| | c | 4 | 1101 | 0100001| | u | 4 | 1011 | 0101000| | i | 3 | 10100 | | ``` 11110001110000011110010111100100101111010010001011011001 100110110001111011101111100110101100000011101110111111100 000000001001101110111110011101111011111111001111101000110 111111011110001010101111111111111101101101001101011101011 011011010000111011011110011111111101101010111000111011100 110001111000101101101000110001111111001111100111001111110 110001101111100100101010118110101011111000001110111101100 111101001011011111111101011111101011011011100110001110011 011110101111111110111001011111011011101111100111100111011 011011010110000001000111100111011001111000101101101101000 000101101011010010111111011110001100011111010111111100011 010010101100111101011101000101011101111001111111010010110 000101111001111000010101101101110010110001110000110000000 000110101000011110001111101001010011001110111101101111001 011111110111111111101000110100000101101011110001010111011 111001010101010110111101010111001110101011110001110010110 001111000111000101110000101011110 ``` 3. Encode the following fax image. There is no need to use zero-length white runs at the beginning of lines starting with a black pixel. ``` ABC ``` 4. Decode the following fax image to the same 37x15 grid. There are no zero-length white runs at the beginning of lines starting with a black pixel. ``` 000010000000000000000111100001000000000011111000000000000 010000000010110000000010100000000000101000000000000111000 011110001110000000110000000000111100001110000011111000000 000111000001101111000000011110001200000111101110000000000 000000000000011010010101000000000111011000001110111000000 000000011111100000000000000011101000000000000011111000000 000000001000001010000000100110010000000000000110011001000 100011101011100000110000111000010001110000111001000000000 ``` #################### File: A%20MACHINE%20MADE%20THIS%20BOOK%20ten%20sketches%20of%20computer%20science%20-%20JOHN%20WHITINGTON%20%28PDF%29.pdf Page: 157 Context: # Chapter 10: Words to Paragraphs The finished paragraphs of type are arranged in a **galley**. This will be used to make prints of the page (or pages – two or four may be printed from one galley, then folded and cut). You can imagine how long it takes to make up the galleys for a book, and how much time is required to justify each line by inserting exactly the right spaces and hyphenating by hand. Mistakes found after test prints can be very costly to fix, since they necessitate taking apart the galleys. #################### File: A%20MACHINE%20MADE%20THIS%20BOOK%20ten%20sketches%20of%20computer%20science%20-%20JOHN%20WHITINGTON%20%28PDF%29.pdf Page: 78 Context: # Chapter 5. Typing it In Again, we choose the tone. Contextual information, such as the previous character, is used to disambiguate the two-character sequence and, in this case, the most common possibility is correct: ## 應去彆 ## 樱桃 Different systems are popular in each part of Asia and in each generation, and depend upon the device in use. Indeed, one person may use a particular system on their computer and entirely another on their mobile phone, which has even less space for keys (real or virtual). We have seen how English and the world’s many other languages might be typed into the computer. There have been many attempts to replace the keyboard for text input, such as voice recognition, which have made some inroads in automotive and niche applications, but for general purpose computing, the keyboard, real or virtual, is still king. #################### File: A%20MACHINE%20MADE%20THIS%20BOOK%20ten%20sketches%20of%20computer%20science%20-%20JOHN%20WHITINGTON%20%28PDF%29.pdf Page: 139 Context: Chapter9.OurTypeface125ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789(cid:362)(cid:363)(cid:364)(cid:365)(cid:366)(cid:367)(cid:368)(cid:369)(cid:370)(cid:371)IJ(cid:276)(cid:277)æœfiflffffiffl(cid:292)(cid:293)(cid:294)(cid:306)st(cid:308)(cid:309)(cid:278)(cid:279)(cid:280)(cid:107)NextaretheSmallCaps,whicharecapitalletterssettothesameheightaslowercaseletters.YoucanseeexamplesofSmallCapsinthefrontmatterofthisbook(thepartsbeforethefirstchapter).Noticethatthesmallcapsarenotjustscaled-downversionsoftheordinarycapitals–havingthesamegeneralweight,theymaybeusedalongsidethem.S(cid:1114)(cid:1102)(cid:1113)(cid:1113)C(cid:1102)(cid:1117)(cid:1120)S(cid:1114)(cid:1102)(cid:1113)(cid:1113)₁₂₃₄₅₆₇₈₉₀N(cid:1122)(cid:1114)(cid:1103)(cid:1106)(cid:1119)(cid:1120)ÄÀÅÁÃĄÂÇäàåáãąâç@£$%¶†‡©¥€`'``''!?(){}:;,./(cid:106)Next,wehaveaccentedletters,ofwhichonlyatinyportionareshownhere.Accentsattachindifferentplacesoneachletter,somanytypefacescontainanaccentedversionofeachcommonletter-accentpair,togetherwithseparateaccentmarkswhichcanbecombinedwithotherlettersasrequiredformoreesotericuses.S(cid:1114)(cid:1102)(cid:1113)(cid:1113)C(cid:1102)(cid:1117)(cid:1120)S(cid:1114)(cid:1102)(cid:1113)(cid:1113)₁₂₃₄₅₆₇₈₉₀N(cid:1122)(cid:1114)(cid:1103)(cid:1106)(cid:1119)(cid:1120)ÄÀÅÁÃĄÂÇäàåáãąâç@£$%¶†‡©¥€`'``''!?(){}:;,./(cid:106)Finally,herearesomeofthemanyotherglyphsinPalatino,forcurrencysymbolsandsoforth,andsomeofthepunctuation:S(cid:1114)(cid:1102)(cid:1113)(cid:1113)C(cid:1102)(cid:1117)(cid:1120)S(cid:1114)(cid:1102)(cid:1113)(cid:1113)₁₂₃₄₅₆₇₈₉₀N(cid:1122)(cid:1114)(cid:1103)(cid:1106)(cid:1119)(cid:1120)ÄÀÅÁÃĄÂÇäàåáãąâç@£$%¶†‡©¥€`'``''!?(){}:;,./(cid:106) #################### File: A%20MACHINE%20MADE%20THIS%20BOOK%20ten%20sketches%20of%20computer%20science%20-%20JOHN%20WHITINGTON%20%28PDF%29.pdf Page: 192 Context: 178TemplatesProblem8.2 #################### File: A%20MACHINE%20MADE%20THIS%20BOOK%20ten%20sketches%20of%20computer%20science%20-%20JOHN%20WHITINGTON%20%28PDF%29.pdf Page: 167 Context: Solutions153b)Theloveof\$\$\$istherootofallevil.c)Theloveof$\$\$\$$istherootofallevil.d)Theloveof*\$$\$$\$*istherootofallevil.Chapter41a)Thepatterndoesnotmatch.b)Thepatternmatchesatposition17.c)Thepatternmatchesatpositions28and35.d)Thepatternmatchesatposition24.2a)Thetextsaa,aaa,andaaaetc.match.b)Thetextsacandabconlymatch.c)Thetextsac,abc,andabbcetc.match.d)Thetextsad,abd,acd,abbd,accd,abcd,acbd,andabbbdetc.match.3a)Thepatternmatchesatpositions16and17.b)Thepatternmatchesatpositions0and24.c)Thepatternmatchesatpositions0,1,24,and25.d)Thepatternmatchesatpostiions0,1,24,and25. #################### File: 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Chapter7.DoingSums91checkthatitworks(again,inourshortenedformofdiagram):reverse[1,2,3]=⇒reverse[2,3]•[1]=⇒(reverse[3]•[2])•[1]=⇒(([3]•reverse[])•[2])•[1]=⇒(([3]•[])•[2])•[1]=⇒[3,2,1]Letusapproachamorecomplicatedproblem.Howmightwesortalistintonumericalorder,whateverorderitisintostartwith?Forexample,wewanttosort[53,9,2,6,19]toproduce[2,6,9,19,53].Theproblemisalittleunapproachable–itseemsrathercomplex.Onewaytobeginistoseeifwecansolvethesimplestpartoftheproblem.Welljustlikeforreverse,sortingalistoflengthzeroiseasy–thereisnothingtodo:sortl=ifl=[]then[]else...Ifthelisthaslengthgreaterthanzero,ithasaheadandatail.Assumeforamomentthatthetailisalreadysorted–thenwejustneedtoinserttheheadintothetailatthecorrectpositionandthewholelistwillbesorted.Hereisadefinitionforsort,assumingwehaveaninsertfunction(weshallconcoctinsertinamoment):sortl=ifl=[]then[]elseinsert(headl)(sort(taill))Ifthelistisempty,wedonothing;otherwise,weinserttheheadofthelistintoitssortedtail.Assuminginsertexists,hereisthewholeevaluationofoursortingprocedureonthelist[53,9,2,6,19],showingonlyusesofsortandinsertforbrevity:sort[53,9,2,6,19]=⇒insert53(sort[9,2,6,19])=⇒insert53(insert9(sort[2,6,19]))=⇒insert53(insert9(insert2(sort[6,19])))=⇒insert53(insert9(insert2(insert6(sort[19])))) #################### File: A%20MACHINE%20MADE%20THIS%20BOOK%20ten%20sketches%20of%20computer%20science%20-%20JOHN%20WHITINGTON%20%28PDF%29.pdf Page: 26 Context: 12Chapter1.PuttingMarksonPaperProblemsSolutionsonpage147.Gridsforyoutophotocopyorprintouthavebeenprovidedonpage173.Alternatively,usegraphpaperordrawyourowngrids.1.Givesequencesofcoordinateswhichmaybeusedtodrawthesesetsoflines.0246810121416182002468101214161820xy0246810121416182002468101214161820xy2.Drawthesetwosequencesofcoordinatesonseparate20x20grids,withlinesbetweenthepoints.Whatdotheyeachshow?(5,19)—(15,19)—(15,16)—(8,16)—(8,12)—(15,12)—(15,9)—(8,9)—(8,5)—(15,5)—(15,2)—(5,2)—(5,19)(0,5)—(10,10)—(5,0)—(10,3)—(15,0)—(10,10)—(20,5)—(17,10)—(20,15)—(10,10)—(15,20)—(10,17)—(5,20)—(10,10)—(0,15)—(3,10)—(0,5)3.Giventhefollowinglineson20x20grids,selectpixelstoap-proximatethem. #################### File: A%20MACHINE%20MADE%20THIS%20BOOK%20ten%20sketches%20of%20computer%20science%20-%20JOHN%20WHITINGTON%20%28PDF%29.pdf Page: 148 Context: 134Chapter9.OurTypefaceProblemsSolutionsonpage166.Thefollowingwordshavebeenbadlyspaced.Photocopyorprintoutthispage,cutouttheletters,andthenpastethemontoanotherpagealongastraightline,findinganarrangementwhichisneithertootightnortooloose.1.Palatino2.AVERSION3.Conjecture #################### File: A%20MACHINE%20MADE%20THIS%20BOOK%20ten%20sketches%20of%20computer%20science%20-%20JOHN%20WHITINGTON%20%28PDF%29.pdf Page: 57 Context: Chapter4.LookingandFinding43Ifwereachasituationwherethewordoverrunstheendofthetext,westopimmediately–nofurthermatchcannowbefound:12T01234567890123456789012345678housesandhorsesandhearsesW012345horsesLetustrytowriteouralgorithmoutasacomputerprogram.Aprogramisasetofinstructionswritteninalanguagewhichisunderstandableandunambiguous,bothtothecomputerandtothehumanbeingwritingit.First,weshallassumethatthepartoftheprogramforcomparingthewordwiththetextatagivenpositionalreadyexists:wewillwriteitlater.Fornow,weshallconcentrateonthepartwhichdecideswheretostart,wheretostop,movesthewordalongthetextposition-by-position,andprintsoutanypositionswhichmatch.Forreasonsofconciseness,wewon’tusearealprogramminglanguagebutaso-calledpsuedocode–thatistosay,alanguagewhichcloselyresemblesanynumberofprogramminglanguages,butcontainsonlythecomplexitiesneededfordescribingthesolutiontoourparticularproblem.First,wecandefineanewalgorithmcalledsearch:definesearchpt1Weusedthekeyworddefinetosaythatwearedefininganewalgorithm.Keywordsarethingswhicharebuiltintotheprogram-minglanguage.Wewritetheminbold.Thenwegaveitthenamesearch.(Thisisarbitrary–wecouldhavecalleditcauliflowerifwehadwanted.)Wegivethenameofthethingthisalgorithmwillworkwith,calledaparameter–inourcasept,whichwillbeanumberkeepingtrackofhowfaralongthesearchingprocessweare(ptforpositionintext).Weshallarrangeforthevalueofpttobeginat0–thefirstcharacter.Ouralgorithmdoesn’tdoanythingyet–ifweaskedthecomputertorunit,nothingwouldhappen.Now,whatweshouldliketodoistomakesurethatwearenotoverrunningtheendofthetext–ifweare,therecanbenomorematches.WearenotoverrunningifthepositionptaddedtothelengthofthewordWislessthanorequaltothelengthofthetextT,thatistosaybetweenthesetwopositions: #################### File: A%20MACHINE%20MADE%20THIS%20BOOK%20ten%20sketches%20of%20computer%20science%20-%20JOHN%20WHITINGTON%20%28PDF%29.pdf Page: 113 Context: # Chapter 8. Grey Areas If we have to manually pick a suitable threshold for each image in a book to get even an acceptable result, the process is going to be time consuming. Here is our black to white gradient at 40%, 50%, and 60% thresholds: | Threshold | Image | |-----------|------------------------------------------| | 40% |  | | 50% |  | | 60% |  | These images bear almost no resemblance to the original. Before describing some more advanced methods for grey tone reproduction, like the one used to make the images at the head of this chapter, we shall take a brief historical detour—the problem of reproducing grey tones is not intrinsically one of computer printing, but has been important in newspaper and print production for hundreds of years. The process of printing is essentially one of duplication. In former times, if we wanted just one of something, we could have a painter paint it, or a scribe write it down. We might even be able to create a copy through direct manual techniques. #################### File: A%20MACHINE%20MADE%20THIS%20BOOK%20ten%20sketches%20of%20computer%20science%20-%20JOHN%20WHITINGTON%20%28PDF%29.pdf Page: 24 Context: 10Chapter1.PuttingMarksonPaperNow,wecanproceedtodesignamethodtofilltheshape.Foreachrowoftheimage,webeginontheleft,andproceedrightwardpixel-by-pixel.Ifweencounterablackdot,weremember,andenterfillingmode.Infillingmode,wefilleverydotblack,untilwehitanotherdotwhichwasalreadyblack–thenweleavefillingmode.Seeinganotheralready-blackdotputsusbackintofillingmode,andsoon.Intheimageabove,twolineshavebeenhighlighted.Inthefirst,weentertheshapeonceatthesideoftheroof,fillacross,andthenexititattherighthandsideoftheroof.Inthesecond,wefillasection,exittheshapewhenwehitthedoorframe,enteritagainattheotherdoorframe–fillingagain–andfinallyexitit.Ifwefollowthisprocedureforthewholeimage,thehouseisfilledasexpected.Theimageontheleftshowsthenewdotsingrey;thatontherightthefinalimage.Noticethatthewindowsanddoordidnotcauseaproblemforourmethod.Wehavenowlookedattheverybasicsofhowtoconvertde-scriptionsofshapesintopatternsofdotssuitableforaprinterorscreen.Inthenextchapter,wewillconsiderthemorecomplicated #################### File: A%20MACHINE%20MADE%20THIS%20BOOK%20ten%20sketches%20of%20computer%20science%20-%20JOHN%20WHITINGTON%20%28PDF%29.pdf Page: 180 Context: 166SolutionsChapter91Palatino2AVERSION3ConjectureChapter101hy-phen-a-tion2fund-raising3a-rith-me-tic(thenoun)4ar-ith-me-tic(theadjective)5dem-on-stra-tion #################### File: A%20MACHINE%20MADE%20THIS%20BOOK%20ten%20sketches%20of%20computer%20science%20-%20JOHN%20WHITINGTON%20%28PDF%29.pdf Page: 152 Context: 138Chapter10.WordstoParagraphsatanypointtoaddingorremovingspacebetweenwords.Theparagraphontherightfollowsusualtypesettingandhyphenationrules,preferringtheaddingofspacetohyphenation.Onemorning,whenGregorSamsawokefromtrouble-ddreams,hefoundhims-elftransformedinhisbedintoahorriblevermin.Helayonhisarmour-likeback,andifheliftedhisheadalittlehecouldseehisbrow-nbelly,slightlydomedanddividedbyarchesintostiffsections.Onemorning,whenGre-gorSamsawokefromtrou-bleddreams,hefoundhimselftransformedinhisbedintoahorriblevermin.Helayonhisarmour-likeback,andifheliftedhisheadalittlehecouldseehisbrownbelly,slightlydomedanddividedbyarchesintostiffsections.Theseareveryuglyhyphenations,however:wehave“trouble-d”,“hims-elf”,and“brow-n”.Everywordhasplaceswhicharebetterorworseforhyphenation.Wewouldprefer“trou-bled”and“him-self”.Ideally“brown”shouldnotbehyphenatedatall.Somewordsmustbehyphenateddifferentlydependingoncontext:“rec-ord”forthenoun,“re-cord”fortheverb,forexample.Inaddition,authoritiesonhyphenation(suchasdictionarieswhichincludehyphenationinformation)donotalwaysagree:Websterhas“in-de-pen-dent”and“tri-bune”,AmericanHeritagehas“in-de-pend-ent”and“trib-une”.Therearewordswhichshouldneverbehyphenated.Forexample,thereisnoreallygoodplacetobreak“squirm”.Therearetwomethodsforsolvingthisproblemautomaticallyasthecomputertypesetsthelines:adictionary-basedsystemsimplystoresanentirewordlistwiththehyphenationpointsforeachword.Thisensuresperfecthyphenationforknownwords,butdoesnothelpusatallwhenanewwordisencountered(asitoftenisinscientificortechnicalpublications,orifweneedtohyphenateapropernoun,suchasathenameofapersonorcity).Thealternativeisarule-basedsystem,whichfollowsasetofrulesaboutwhataretypicallygoodandbadbreaks.Forexample“abreakisalwaysallowableafter“q”iffollowedbyavowel”or“ahyphenisfinebefore-ness”or“ahyphenisgoodbetween“x”and“p”inallcircumstances”.Wemayalsohaveinhibitingrulessuchas“neverbreakb-ly”.Somepatternsmayonlyapplyatthebeginningorendofaword,othersapplyanywhere.Infact,theserulescanbeder #################### File: A%20MACHINE%20MADE%20THIS%20BOOK%20ten%20sketches%20of%20computer%20science%20-%20JOHN%20WHITINGTON%20%28PDF%29.pdf Page: 65 Context: Chapter4.LookingandFinding51realise.Thereareotherspecialcharacters:wecanuseafullstop.tomatchanycharacter,sothatthepattern.uncematchesounceanddunce.Inadditiontothesepatterns,wecanrunasearchmultipletimesandcombinetheresults.Forexample,whenusinganinternetsearchengine,ifweareinterestedinfindingdocumentscontaining“cats”or“dogs”wemightenterthesearch“catsORdogs”.ThesearchengineknowsthatthewordORisspecial,anditrunstwosearches,onefor“cats”andonefor“dogs”andreturnsdocumentswhichcontainaninstanceofeither.Inreality,searchenginesdon’tlookthroughthetextofwebpagesatthemomentthatyouclickthesearchbutton:theyusepre-preparedindexestomakethesearchmanymanytimesfaster.Intheproblemswhichfollow,weextendthisideaofpatterns,andaskyoutorunthesearchingalgorithmthroughonpapertodeterminewhethertheymatchthetext. #################### File: 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Chapter3.StoringWords33f102t116e101p112space32h104,44y121a97e101space32"34l108space32"34Therearemanymorecharactersintheworldthanthese,andthereforemanyproprietaryandcompetingmethodsforextendingthistable.Theseincludetheadditionofaccentedcharactersinthewesternlanguages,andtheuseofothermethodsaltogetherfortheworld’sothercharactersets;forexample,theCyrilliccharactersofRussian,theHancharactersofChinese,andthemanywritingmethodsoflanguagesfromtheIndiansubcontinent.Weshallexaminesomeoftheselaterinthischapter.WehaveusedtheCarriageReturnandLineFeedcharacterstochangethewayourtextislaidout(sometimescalledformatting).However,wehavenotseenhowtochangethetypeface,typeshape,typethickness,orthesizeofthetext.Weshouldliketobeabletointro-ducesuchchangesduringtherunofthetext,asinthisparagraph.Whatisneededisawayto“markup”thetextwithannotationssuchas“makethiswordbold”or“changetotypesize8pthere”.Suchmethodsareknownasmark-uplanguages.Wecouldimagineasystemwheretyping,forexample,“This*word*mustbebold”intothecomputerwouldproduce“Thiswordmustbebold”ontheprintedpageorelectronicdocument.Wecoulduseasymbolforeachotherkindofchange–forexample,$foritalic–sowecanwrite“$awful$”andget“awful”.Aproblemarises,though.Whatifwewishtotypealiteral$character?Wemustescapetheclutchesofthespecialformattingsymbolstem-porarily.Wedosousingwhatiscalledanescapecharacter.Themostcommonis\(theso-calledbackslash).Wesaythatanycharacterim-mediatelyfollowingtheescapecharacteristoberenderedliterally.So,wecanwrite“And$especially$for\$10”toproduce“Andespeciallyfor$10”.Howthendowetypeabackslashitself?Well,thebackslashcanescapeitselfjustaswell!Wesimplywrite\\.So,theliteraltext“The\\character”produces“The\character”.Letuslookathowsomecommonmark-upsystemsrepresentthefollowingpieceofformattedtext:SectionTitleThisisthefirstparagraph,whichisimportant. 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88Chapter7.DoingSumsIfyisgreaterthan0,ontheotherhand,wewanttocalculatextimesxy−1:powerxy=ify=0then1elsex×powerx(y−1)So,wecannowcalculate25,showingjusttheimportantsteps:power25=⇒2×power24=⇒2×(2×power23)=⇒2×(2×(2×power22))=⇒2×(2×(2×(2×power21)))=⇒2×(2×(2×(2×(2×power20))))=⇒2×(2×(2×(2×(2×1))))=⇒32Wehavelookedatnumberslike2and32,andthetruthvaluestrueandfalse,butinterestingprogramsoftenhavetooperateonmorecomplicatedstructures.Onesuchisalist,whichwewritewithsquarebracketsandcommas,likethis:[1,5,4].Alistisanorderedcollectionofothervalues.Thatistosay,thelists[1,5,4]and[5,4,1]aredifferent,eventhoughtheycontainthesamevalues.Thereisanemptylist[]whichcontainsnoitems.Thefirstelementofalistiscalledthehead,andthereisabuilt-infunctiontogetatit:head[1,5,4]=⇒1Therestoftheelementsarecollectivelyreferredtoasthetail,andagainthereisabuilt-infunctiontoretrieveit:tail[1,5,4]=⇒[5,4]Theemptylist[]hasneitheraheadnoratail.Weneedjustonemorethingforourexampleprograms,andthatisthe•operatorwhichstickstwoliststogether:[1,5,4]•[2,3]=⇒[1,5,4,2,3] 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Chapter4LookingandFindingWhenwritingabook,itisimportanttobeabletowrangleefficientlyalongpieceoftext.Oneimportanttaskistosearchforaword,find-ingwhereithasbeenused:wemaythenjumptosuchapositioninthetext,seewhatisaroundtheword,andmodifyorreplaceit.Weneedtodothisondemand,withoutanexplicitlypreparedindex.Infact,wehaveindexesatthebackofbooksbecausesearchingthroughthebookmanually,fromfronttoback,isslowanderrorproneforahuman.Luckily,itisfastandaccurateforacomputer.Itmightseemthatitiseasytodescribetoacomputerhowtosearchforaword:justlookforit!Butwemustprepareanexplicitmethod,madeoftinylittlesimplesteps,forthecomputertofollow.Everythingmustbeexplainedinperfectdetail–nobigassumptions,nohand-waving.Suchacareful,explicitmethodiscalledanalgorithm.Whatarethebasicoperationsfromwhichwecanbuildsuchanalgorithm?Assumewehavethetexttobesearched,andthewordtosearchfor,athand.Eachofthemismadeupofcharacters(A,x,!etc).Assumealsothatweknowhowtocomparetwocharacterstoseeiftheyarealikeordifferent.Forexample,AisthesameasAbutdifferentfromB.Letuspickaconcreteexample:weshalltrytofindtheword“horses”inthetext“housesandhorsesandhearses”.Letusnumbereachofthe29charactersinthetextandthe6charactersintheword:41 #################### File: A%20MACHINE%20MADE%20THIS%20BOOK%20ten%20sketches%20of%20computer%20science%20-%20JOHN%20WHITINGTON%20%28PDF%29.pdf Page: 168 Context: 154SolutionsChapter61LetterFrequencyCodeLetterFrequencyCodespace41111u5110100e18100v4110011o141011w4110010t140111f4110001a130110’4010111h120100y3010101r110011.301010000n110010,301010001s100000p201010010i911011I201010011c810101q101011000m610100E101011001l600011S101011010g6110101T101011011Sowehave:'Ihavea01011101010011111010001101100111001110110111theorywhi0111010010010110011010101111110010010011011chIsusp101010100111010100111110000110100000001010010ectisrath1001010101111111101100001110011011001110100erimmoral100001111111011101001010010110011011000011,'Smiley0101000101011111101011010101001101100011100010101wenton,111110010100001001111111011001001010001111morelight1010010110011100111000111101111010101000111ly.0001101010101010000 #################### File: A%20MACHINE%20MADE%20THIS%20BOOK%20ten%20sketches%20of%20computer%20science%20-%20JOHN%20WHITINGTON%20%28PDF%29.pdf Page: 193 Context: Templates179Problem8.3 #################### File: A%20MACHINE%20MADE%20THIS%20BOOK%20ten%20sketches%20of%20computer%20science%20-%20JOHN%20WHITINGTON%20%28PDF%29.pdf Page: 121 Context: # Chapter 8. Grey Areas ## Figure G: Film grain  ## Figure H: Film under an electron microscope  #################### File: A%20MACHINE%20MADE%20THIS%20BOOK%20ten%20sketches%20of%20computer%20science%20-%20JOHN%20WHITINGTON%20%28PDF%29.pdf Page: 144 Context: 130Chapter9.OurTypefaceWehavelookedatsomeofthesurprisingcomplexitiesofasimpletypeface,andhowitscharactersarepickedandplacednexttoeachothertoformlines.TypefacesforEasternalphabetsandwritingsystemsareevenmorecomplex.Tofinish,weexhibitthefull1328glyphsofthePalatinoRomantypefaceonthenextthreepages.Canyouworkoutwhateachglyphisusedfor? #################### File: A%20MACHINE%20MADE%20THIS%20BOOK%20ten%20sketches%20of%20computer%20science%20-%20JOHN%20WHITINGTON%20%28PDF%29.pdf Page: 177 Context: # Chapter 8 1 | | | | | |---|---|---|---| | | ▓ | | | | ▓ | ▓ | | | | ▓ | ▓ | ▓ | ▓ | | ▓ | ▓ | ▓ | | | | | ▓ | | | | | | ▓ | | | | | |   #################### File: A%20MACHINE%20MADE%20THIS%20BOOK%20ten%20sketches%20of%20computer%20science%20-%20JOHN%20WHITINGTON%20%28PDF%29.pdf Page: 85 Context: Chapter6.SavingSpace71h0100c110010q01011001o0011u110001x110000100r0010y010111W010110001n0000f010101K010110000s11011b010100I1100001011d10101v000101B1100001010Theinformationinthistablecan,alternatively,beviewedasadiagram:n,vwrohbfKWq.yiaeldtTjxBIkucgmpsspaceInordertofindthecodeforaletter,westartatthetop,adding0eachtimewegoleftand1eachtimewegoright.Forexample,wecanseethatthecodefortheletter“g”isRightRightLeftLeftRightRightor110011.Youcanseethatallthelettersareatthebottomedgeofthediagram,avisualreinforcementoftheprefixproperty.Thecompressedmessagelengthforourexampletextis4171bits, #################### File: A%20MACHINE%20MADE%20THIS%20BOOK%20ten%20sketches%20of%20computer%20science%20-%20JOHN%20WHITINGTON%20%28PDF%29.pdf Page: 96 Context: 82Chapter7.DoingSumsNotethatforthistowork,wehavetoparenthesiseevenexpressionswheretheparenthesescannotaffecttheresult,forexample1+(2+(3+4)).Itcanbedifficultforhumanstoreadsuchover-parenthesisedex-pressions(whichiswhymathematiciansusetheminimumnumberofparenthesesandrelyonasetofad-hocrulesfordisambiguation–theinsistenceonexplicitprecisenesscanactuallybeantitheticaltodoingmathematics).Forcomputers,however,thisrepresentationisideal.Wecanseethestructureoftheseexpressionsmoreclearlybydrawingthemlikethis:+×321isthesameas1+(2×3)Thesearecalledtrees,becausetheyhaveabranchingstructure.Unlikerealtrees,wedrawthemupside-down,withtherootatthetop.Wecanshowthestepsofevaluation,justasbefore,withouttheneedforanyparentheses:+×321=⇒+61=⇒7Infact,thisistherepresentationacomputerwoulduseinter-nally(notliteraldrawings,ofcourse,butastructureofthisforminitsmemory).Whenwetypeinacomputerprogramusingthekeyboard,wemightwrite1+2*3.(Thereisno×keyonthekeyboard.)Itwillbeconvertedintotreeformandcanthenbeevaluatedautomatically,andquickly,bythecomputer.Whenwewriteinstructionsforcomputers,wewantasinglesetofinstructionstoworkforanygiveninput.Todothis,wewriteourexpressions–justlikeinmaths–tousequantitieslikexandyand #################### File: A%20MACHINE%20MADE%20THIS%20BOOK%20ten%20sketches%20of%20computer%20science%20-%20JOHN%20WHITINGTON%20%28PDF%29.pdf Page: 103 Context: Chapter7.DoingSums89Letuswriteafunctiontofindthelengthofalistusingthetailfunction:lengthl=ifl=[]then0else1+length(taill)Theemptylisthaslength0,andthelengthofanyotherlistis1plusthelengthofitstail.Noticethatthe=operatorworksonliststoo.Wecantryasampleevaluation:length[2,3]=⇒if[2,3]=[]then0else1+length(tail[2,3])=⇒iffalsethen0else1+length(tail[2,3])=⇒1+length(tail[2,3])=⇒1+length[3]=⇒1+if[3]=[]then0else1+length(tail[3])=⇒1+iffalsethen0else1+length(tail[3])=⇒1+(1+length(tail[3]))=⇒1+(1+length[])=⇒1+(1+if[]=[]then0else1+length(taill))=⇒1+(1+iffalsethen0else1+length(taill))=⇒1+(1+0)=⇒1+1=⇒2Thesediagramsarebecomingalittleunwieldy,soaswewritemorecomplicatedfunctions,wewillleavesomeofthedetailout,concentratingontherepeatedusesofthemainfunctionwearewriting,herelength:length[2,3]=⇒1+length[3]=⇒1+(1+length[])=⇒1+(1+0)=⇒2 #################### File: A%20MACHINE%20MADE%20THIS%20BOOK%20ten%20sketches%20of%20computer%20science%20-%20JOHN%20WHITINGTON%20%28PDF%29.pdf Page: 163 Context: Solutions149Chapter21WeassignthelettersABCDasinthechaptertext:ABCDNow,wecontinuetheconstructionasbefore,makingsurewearenotconfusedbythefactthatthelineBCnowcrossesthecurve: #################### File: A%20MACHINE%20MADE%20THIS%20BOOK%20ten%20sketches%20of%20computer%20science%20-%20JOHN%20WHITINGTON%20%28PDF%29.pdf Page: 191 Context: Templates177Problem8.1 #################### File: A%20MACHINE%20MADE%20THIS%20BOOK%20ten%20sketches%20of%20computer%20science%20-%20JOHN%20WHITINGTON%20%28PDF%29.pdf Page: 40 Context: 26Chapter2.LetterFormsProblemsSolutionsonpage149.1.PrintoutortracethefollowingBéziercurve,anddivideitintotwo,usingtheprocedureofdeCasteljau.Youwillneedapencilandruler.2.Ifyouhaveaccesstoacomputer,findadrawingprogramwithBéziercurves,andexperimenttogainanintuitiveun-derstandingofhowtheyaremanipulated.Atthetimeofwriting,onesuchfreeprogramisInkscape,suitableformostcomputers.3.Fillinthefollowingshapesusingtheeven-oddfillingruleandagainusingthenon-zerofillingrule.Thedirectionofeachlineisindicatedbythelittlearrows.Thesecondandthirdpicturescontaintwoseparate,overlappingsquarepaths. #################### File: A%20MACHINE%20MADE%20THIS%20BOOK%20ten%20sketches%20of%20computer%20science%20-%20JOHN%20WHITINGTON%20%28PDF%29.pdf Page: 140 Context: 126Chapter9.OurTypefaceS(cid:1114)(cid:1102)(cid:1113)(cid:1113)C(cid:1102)(cid:1117)(cid:1120)S(cid:1114)(cid:1102)(cid:1113)(cid:1113)₁₂₃₄₅₆₇₈₉₀N(cid:1122)(cid:1114)(cid:1103)(cid:1106)(cid:1119)(cid:1120)ÄÀÅÁÃĄÂÇäàåáãąâç@£$%¶†‡©¥€`'``''!?(){}:;,./(cid:106)Howdowepicklettersfromthetypefaceandplacethemonthepage?Eachglyphcontainsnotonlythelinesandcurveswehavediscussedearlierinthebooks,butwhatareknownasmetrics;thatistosayasetofnumbersgoverninghowtheletterrelatestoitspreviousoneshorizontally,andwhereitliesvertically.Variousofthesenumberscanbeusedtofitletterstogetherpleasingly.Themostimportantmetricsarethebaselineandtheadvancement.Thebaselineisjustlikethelineonaschoolchild’sruledpaper–capitalletterssitonit,letterswithdescenderslike“g”and“y”dropsome-whatbelowit.Everyglyphisdefinedinrelationtothisbaseline,sowecanplaceitinthecorrectverticalposition.Theadvancementtellsushowmuchtomovetotherightafterdrawingtheglyph;thatistosay,howfartheoriginhasmoved.So,atthebeginningofaline,westartatanx-coordinateofzeroandmoverightwardsbytheadvancementeachtime.BaselineAdvancementBounding BoxAscentDescentThediagramshowsthreeglyphs,showingvariousmetrics:someareneededforplacingthemonthepageandsomeinfor-mationusedforotherpurposes.Thepositionofthelettersinalinedependsnotonlyontheindividualcharacters(theletter“i”ismuchnarrowerthantheletter“w”,forexample),butonthecombinationsinwhichtheyareprinted.Forexample,acapitalVfollowedbyacapitalAlooksoddifthespacingisnottightened: #################### File: A%20MACHINE%20MADE%20THIS%20BOOK%20ten%20sketches%20of%20computer%20science%20-%20JOHN%20WHITINGTON%20%28PDF%29.pdf Page: 188 Context: 174TemplatesProblem1.20246810121416182002468101214161820xy0246810121416182002468101214161820xyProblem1.30246810121416182002468101214161820xy0246810121416182002468101214161820xy #################### File: A%20MACHINE%20MADE%20THIS%20BOOK%20ten%20sketches%20of%20computer%20science%20-%20JOHN%20WHITINGTON%20%28PDF%29.pdf Page: 54 Context: 40Chapter3.StoringWordsProblemsSolutionsonpage151.1.UsingthemethodofPolybius,encodethephrase“MARY-HADALITTLELAMB”.Howmanycharactersareinthemes-sage?Howmanynumbersareneededtoencodethem?Canyouthinkofawaytoindicatetheconceptof“endofmessage”inPolybius’ssystem?Whataboutspaces?2.Completeatableofbits,numbers,andlettersforasystemwhichusesfivebitsforeachcharacter.Howmanylinesdoesthetablehave?Whichcharactersdidyoudeemimportantenoughtoinclude?3.DecodethefollowingmessagefromASCII:8411410197115111110105115118101114121109117991049710997116116101114111102104979810511644831091051081011211001019910510010110046.4.EncodethefollowingmessageintoASCII:Themoreidentitiesamanhas,themoretheyexpressthepersontheyconceal.5.Inamark-uplanguageinwhich\istheescapecharacter,andapairof$saroundawordmeansitalicandapairof*saroundawordmeanbold,givethemarked-uptextforthefollowingliteralpiecesoftext:a)Theloveofmoneyistherootofallevil.b)Theloveof$$$istherootofallevil.c)Theloveof$$$istherootofallevil.d)Theloveof$$$istherootofallevil. 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Chapter9.OurTypeface127AVAVInthisexample,thereisnotighteningintheleft-handexample,buttighteninghasbeenappliedtotheright-handone.Suchtight-eningiscalledkerning.HerearesomeoftherulesfromPalatinoshowinghowmuchextraspaceisaddedorremovedwhenthecharacters“A”,“a”,“:”etc.followthecharacter“V”.VA-111Vhyphen-74Vr-92Va-92Vi-55Vsemicolon-55Vcolon-55Vo-111Vu-92Vcomma-129Vperiod-129Vy-92Ve-111VA-111VOslash-37VOE-37Vae-148Voslash-130Voe-130VAring-130Vquoteright28Thenumbersareexpressedinthousandthsofaninch.Forexample,youcanseethatwhenahyphenfollowsa“V”,thehyphenisplaced74/1000ofaninchclosertothe“V”.Kerningisespeciallyimportantwhenlettersmeetpunctuation.Palatinohad,inall,1031suchrulesforpairsofcharacters.Overlappingofadjacentletterscanalsobeachievedsimplybyextendingtheshapeofthecharacterbeyonditsboundingbox.ThefollowingdiagramshowstheparticularlystrikingoverlapsusedbythevariousalternativecharactersavailableinanotherofZapf’screations,thescript-likeZapfino.dawningdawningdawningdawningdawningdawningdawningdawning 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INDEXJointPhotographicExpertsGroup,75JPEG,75justificationfull,136,137KafkaFranz,135kerning,127,136keyboard,27,53keyword,43laserprinter,4Latinalphabet,61leading,136ligature,50,124lineantialiased,8drawing,5linefeed,31LinearA,39linesperinch,108liningnumbers,124Linotype,123list,88reversing,90sorting,91lossycompression,74LouisSteinberg,118lpi,108mark-up,33mezzotint,102microtypography,139ModernGreek,61,124monitor,8negative,106newspaper,3newsprint,3niello,102non-zerorule,24oldstylenumbers,124operand,85operator,84opticalfontsize,128OR,51ordereddither,114origin,2orphan,139output,27Palatino,15,123paragraph,135parameter,43parenthesesinanexpression,82path,18containingahole,23filling,24self-crossing,24pattern,51PauldeCasteljau,17PDFfile,3photograph,97,106phototypesetting,144PierreBézier,17PierredeFermat,1Pinyin,61pixel,3,15plate,101point,2Polybius,27position,1prefix,70program,43,81psuedocode,43pt,2QWERTYkeyboard,58ragged-right,137RembrandtvanRijn,104Remington&Sons,53RenéDescartes,1 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184IndexDailyGraphic,108DavidA.Huffman,72deCasteljauPaul,17demerit,139DensmoreJames,55DescartesRené,1dictionary,67digitalhalftoning,111DijkstraEdsger,viidither,111ordered,114dotsperinch,3DürerAlbrecht,102DvorakAugust,58Dvorakkeyboard,58eBook,3,34Eckert-MauchlyComputerCorporation,60EDSAC,30EdsgerDijkstra,viiend-point,17engraving,102errordiffusion,118escapecharacter,33etching,104even-oddrule,24expression,81evaluating,81factorial,86false,45,84fax,72compression,72FermatPierrede,1filledshape,9firesignals,27FloydRobertW.,118FranzKafka,135frenchcurves,16frequenciesofcharacters,70fulljustification,136,137function,84galley,143glyphmetrics,126gradient,97Greekalphabet,27greytones,97halftone,106forcolour,114halftonescreen,108Hancharacters,33HermannZapf,123HuffmanDavidA.,72Huffmanencoding,72humanopticalsystem,8hyphenation,137dictionarybased,138if...then...else,44,85imageblackandwhite,98grey,98indenting,44index,41inhibitingrule,138ink-flow,114input,27system,61insert,91intaglio,101interoperability,29italic,34,123JamesDensmore,55 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Chapter1.PuttingMarksonPaper52ptwordwithmagnificationat400x(atypefaceofagivensizeisroughlythatnumberofpointstall,say,foritscapitalletters.)Allthesedotsformahugeamountofinformationwhichiscostlyanddifficulttomanipulate.So,wewillnormallystoreourpagesinamorestructuredway–someparagraphs,whicharemadeofwords,whicharemadeofletters,whicharedrawnfromsometypeface,whichisdefinedusinglinesandcurves.Thehundredsofmillionsofdotswhichwillfinallymakeupthepageonlyexisttemporarilyastheimageisprinted,orplacedontothescreen.(Theexception,ofcourse,iswhenweusephotographsaspartofourpage–thecolourofeachdotiscapturedbythecamera,andwemustmaintainitinthatform.)Untilrecentlythestorage,commu-nication,andmanipulationofhighresolutionphotographswasasignificantproblem.Thestorage,communication,andmanipu-lationofhighresolutionvideostillis–imaginehowmanylittlecoloureddotsmakeupastillimage,thenmultiplyby25or50imagespersecondforthe2hours(7200seconds)afeaturefilmlasts.Wehavetalkedonlyaboutsingledots.However,weshallneedlines,curves,andfilledshapestobuildourpage.Supposethatwewishtodrawaline.Howcanweworkoutwhichdotstopaintblacktorepresenttheline?Horizontalandverticallinesseemeasy–wejustputinkoneachdotinthatroworcolumn,forthewholelengthoftheline.Ifwewantathickerline,wecaninkmultiplerowsorcolumnseithersideoftheoriginalline.Buttherearemanyusefullinesotherthanthehorizontalandverticalones.Tobegin,weshallneedawaytodefinealine.Wecanjustusetwocoordinates–thoseofthepointsateitherend.Forexample,hereistheline(1,1)—(6,3):012345670123xy(6,3)(1,1)Inmathematics,wewouldusuallyconsideralinetobeofinfi-nitelength,andsothisisreallyalinesegment,butweshalljustcallitaline.Noticethatthislinecouldequallybedefinedas(6,3)—(1,1).Asafirststrategy,letustrycolouringinonedotineachcolumnfromcolumn1tocolumn6,wherethelineispresent.Wewill 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Chapter7DoingSumsHowdowecalculatetheanswerto1+2×3?Inourheads,perhaps,oronpaper.Buthowdowedecidewhichoperationtodofirst(the+orthe×?)Well,inmathematics,wehavetheconventionthat,inthissituation,themultiplicationgoesfirst.Sowemayworkasfollows:1+2×3=⇒1+6=⇒7Somethinglike1+2×3isanexampleofamathematicalexpression.(Wehaveunderlinedthepartoftheexpressionbeingworkedonateachstage.)Rewritingitstagebystage,makingitsmallereachtime,untilwereachafinalanswer,iscalledevaluatingtheexpression.Theresultisavalue,whichisanexpressionthatcanbereducednofurther:7isjust7.Wecouldrewriteitas3+4or1+1+5,ofcourse,butwelikeeachsubsequentexpressiontobesimplerthanthelast.Computerprogramsofteninvolvethesekindofexpressions,andindeedinsomeprogramminglanguages,thewholeprogramisjustonebigexpression.Itwouldbesimplerifwecouldrepresentsuchexpressionsinanunambiguousway,sothatwedon’tneedtothinkabouttherulesforwhichoperationshappeninwhichorder.(It’ssimpleinourexample,butexpressionsincomputerprogramscanbehuge.)Wecanjustaddparenthesestotheexpression:1+(2×3).Nowtheruleforchoosingwhattodonextcanbestatedmoresimply:evaluateapartoftheexpressionwhichcontainsnoparenthesesfirst.81 #################### File: A%20MACHINE%20MADE%20THIS%20BOOK%20ten%20sketches%20of%20computer%20science%20-%20JOHN%20WHITINGTON%20%28PDF%29.pdf Page: 124 Context: # Chapter 8: Grey Areas ## Figure J: Small, medium, and large halftone dots.    - Small halftone dots: Represents the lightest parts of the image. - Medium halftone dots: Represents the mid-tones. - Large halftone dots: Represents the darkest parts of the image. #################### File: A%20MACHINE%20MADE%20THIS%20BOOK%20ten%20sketches%20of%20computer%20science%20-%20JOHN%20WHITINGTON%20%28PDF%29.pdf Page: 106 Context: 92Chapter7.DoingSums=⇒insert53(insert9(insert2(insert6(insert19(sort[])))))=⇒insert53(insert9(insert2(insert6(insert19[]))))=⇒insert53(insert9(insert2(insert6[19])))=⇒insert53(insert9(insert2[6,19]))=⇒insert53(insert9[2,6,19])=⇒insert53[2,6,9,19]=⇒[2,6,9,19,53]Nowwemustdefineinsert.Itisafunctionwhichtakestwothings:theitemxtobeinsertedandthe(already-sorted)listlinwhichtoinsertit.Ifthelistisempty,wecansimplybuildthelist[x]:insertxl=ifl=[]then[x]else...Therearetwoothercases.Ifxislessthanorequaltotheheadofthelist,wecanjustputitatthefrontofthelist,andwearedone:insertxl=ifl=[]then[x]elseifx≤headlthen[x]•lelse...Otherwise,wehavenotyetfoundanappropriateplaceforournumber,andwemustkeepsearching.Theresultshouldbeourhead,followedbytheinsertionofournumberinthetail:insertxl=ifl=[]then[x]elseifx≤headlthen[x]•lelse[headl]•insertx(taill)Considertheevaluationofinsert3[1,1,2,3,5,9]:insert3[1,1,2,3,5,9]=⇒[1]•insert3[1,2,3,5,9]=⇒[1]•([1]•insert3[2,3,5,9])=⇒[1]•([1]•([2]•insert3[3,5,9]))=⇒[1]•([1]•([2]•([3]•[3,5,9])))=⇒[1,1,2,3,3,5,9] #################### File: A%20MACHINE%20MADE%20THIS%20BOOK%20ten%20sketches%20of%20computer%20science%20-%20JOHN%20WHITINGTON%20%28PDF%29.pdf Page: 81 Context: Chapter6.SavingSpace67thejudge.Therepliestheyreceivedwerejustasquiet,andgivenbehindtheprotectionofaraisedhand.Weshalltakeasourdictionarythe100mostcommonly-usedEnglishwordsofthreeormoreletters:00the25there50two75part01and26use51more76over02you27each52write77new03that28which53see78sound04was29she54number79take05for30how55way80only06are31their56could81little07with32will57people82work08his33other58than83know09they34about59first84place10this35out60water85year11have36many61been86live12from37then62call87back13one38them63who88give14had39these64its89most15word40some65now90very16but41her66find91after17not42would67long92thing18what43make68down93our19all44like69day94just20were45him70did95name21when46into71get96good22your47time72come97sentence23can48has73made98man24said49look74may99thinkThesewordswillbecompressedbyrepresentingthemasthetwo-charactersequences00,01,02,...,97,98,99.Wedon’tbotherwiththeoneandtwoletterwords,commonthoughtheyare,be-causetheyarealreadyasshortorshorterthanourcodes.Weassumeourtextdoesnotcontaindigits,sothatanydigitsequencemaybeinterpretedasacode.Anyword,text,orpunctuationnotinthewordlistwillberenderedliterally.Ifwesubstitutethesecodesintoourtext,wefindasomewhatunderwhelminglevelof #################### File: A%20MACHINE%20MADE%20THIS%20BOOK%20ten%20sketches%20of%20computer%20science%20-%20JOHN%20WHITINGTON%20%28PDF%29.pdf Page: 120 Context: # Chapter 8. Grey Areas  It might surprise you that even the photographic process has trouble representing grey tones. Photographic film consists of particles of compounds of silver, suspended in a gel. When exposed to light, tiny changes to the crystal structure record an invisible image. When developed, each particle is either converted to silver (which will appear black in the final photograph), or not thus converted (which will appear white). The process of enlarging the photograph from the negative to the positive paper print may introduce greys by dint of its analogue nature, of course, but if enlarged enough, one can see the so-called film grain clearly. Figure G shows an enlargement of a photograph of a plain grey card. Under a powerful electron microscope, in Figure H, we can see the individual crystals on the photographic film. None of the methods we have seen so far allow for the automatic conversion of photographic content to a printable form such as a plate which might be wanted for a daily newspaper. We have a grey tone image, in the form of a photographic negative. Our printing process, however, allows only black and white, so we wish to automatically convert the grey tones to a series of regularly spaced dots whose diameter reflects the level of grey. Here is our gradient, followed by its so-called halftone: #################### File: A%20MACHINE%20MADE%20THIS%20BOOK%20ten%20sketches%20of%20computer%20science%20-%20JOHN%20WHITINGTON%20%28PDF%29.pdf Page: 134 Context: # Chapter 8. Grey Areas ``` 100 | 0 | 100 --- |---|--- 0 | 100 | 0 100 | 0 | 100 ``` Here is our camel picture and gradient processed with the algorithm described above.  You can see that there appear to be much finer gradations of grey and that, whilst the eye can discern some patterns in the flat shaded areas, they are much less distracting than in the case of the ordered dither. Overall, a much more pleasing result. The gradient is much finer too, especially when viewed from a distance. There are several newer variations on this procedure, using more complicated diffusion of errors. #################### File: A%20MACHINE%20MADE%20THIS%20BOOK%20ten%20sketches%20of%20computer%20science%20-%20JOHN%20WHITINGTON%20%28PDF%29.pdf Page: 39 Context: Chapter2.LetterForms25Ourlinecrossestwoanti-clockwiselinesandisthereforenon-zero(ithasacountof0−1−1whichis−2).WecanapplythisruletoourOexampletoo,butthereisaproblem:theinnerholeisfilledtoo:Thiscanbefixedbyreversingthedirectionofeitherofthetwopaths.Wenowhaveamethodwhichworksforbothcases:Nowthatwehavesomeunderstandingofhowtodrawlinesandcurvesontopaperorthescreen,wewillturntotheinput,storage,andmanipulationoftextitself,beforereturningtothevisuallayoutofthepagelaterinthebook. #################### File: A%20MACHINE%20MADE%20THIS%20BOOK%20ten%20sketches%20of%20computer%20science%20-%20JOHN%20WHITINGTON%20%28PDF%29.pdf Page: 111 Context: # Chapter 8 ## Grey Areas With only black ink and white paper, we can draw both beautiful letters and good line drawings, such as the diagrams of Bézier curves from Chapter 2. But what about reproducing photographs? How can we create the intermediate grey tones? Consider the following two images: a photograph of a camel and a rather higher-resolution picture of a smooth gradient between black and white:   We shall use these pictures to compare the different methods of reproduction we discuss. From looking at the page (at least if you are reading this book in physical form rather than on a computer). #################### File: A%20MACHINE%20MADE%20THIS%20BOOK%20ten%20sketches%20of%20computer%20science%20-%20JOHN%20WHITINGTON%20%28PDF%29.pdf Page: 127 Context: # Chapter 8. Grey Areas  As the tone moves from white to black, the spot grows gradually. If you imagine the patterns tiled repeatedly across the page, you can see that the white sections left in the corners as the black spot grows themselves form white spots. Thus, we have a smooth transition. Here is the result of dithering these patterns for the camel and the gradient:  --- Prop this book up against a wall, retreat to the other side of the room (or perhaps halfway), and see which looks more camel-like. What about at normal reading distance? Such halftone patterns are used in most modern printing. Here are microscopic pictures of the camel as it is printed at the head of this chapter, at 20x and 400x magnification:   #################### File: A%20MACHINE%20MADE%20THIS%20BOOK%20ten%20sketches%20of%20computer%20science%20-%20JOHN%20WHITINGTON%20%28PDF%29.pdf Page: 90 Context: # Chapter 6. Saving Space | Description | Image | |---------------------|----------------| | original – 100% |  | | 64 greys – 40% |  | | 8 greys – 14% |  | | 2 greys – 5% |  | **Figure A** | Description | Image | |---------------------|----------------| | all pixels |  | | 1/2 discarded |  | | 3/4 discarded |  | | 7/8 discarded |  | **Figure B** #################### File: A%20MACHINE%20MADE%20THIS%20BOOK%20ten%20sketches%20of%20computer%20science%20-%20JOHN%20WHITINGTON%20%28PDF%29.pdf Page: 112 Context: # Chapter 8: Grey Areas When viewing the page from a normal reading distance, you can see that it is indeed possible. But how? The simplest method of converting a grey image into a black and white one is simply to pick a level of grey above which we consider each part of the image black and below which we consider it white. Here is our camel, printed using black ink for any part which is more than 50% black (i.e. a mid grey), and no ink for any part which is less than 50% black:  Well, we can see the shape of the camel, but the result is less than spectacular. Let's try moving the threshold to 40%:  We can’t see as much detail of the camel in this case, but at least its legs are solid. If we move the other way, to a threshold of 60%, things get even worse:  #################### File: A%20MACHINE%20MADE%20THIS%20BOOK%20ten%20sketches%20of%20computer%20science%20-%20JOHN%20WHITINGTON%20%28PDF%29.pdf Page: 23 Context: Chapter1.PuttingMarksonPaper9ortheirexistenceorabsence,isthedensityoflightsensitivecellsontheretina.Atadistanceof12inches,adensityof600dotsperinchontheprintedpagemayberequired.Forabillboard,wemayonlyneed20or50dotsperinch.Onascreen,antialiasingallowsustousealowerresolutionthanwemightotherwiseneed.Wehaveseenhowtodrawlinesbetweenpoints,andsowecanbuildshapesbychainingtogethermultiplelines.Forexam-ple,thelines(1,1)—(10,1),(10,1)—(10,10),(10,10)—(1,10),and(1,10)—(1,1)formasquare(youcandrawitonpaperifyouwish).Wemightdefinethismoreconciselyas(1,1)—(10,1)—(10,10)—(1,10)—(1,1).However,ifwewishtoproduceafilledshape(suchasaletterinaword)wewouldhavetomakeitupfromlotsoflittlehorizontallinesorlotsoflittleverticalones,tomakesurethateverydotwewantedtobecoveredwascovered.Weshouldliketoautomatethisprocess,soastoavoidmanuallyspecifyingeachpartofthefilledsection.Considerthefollowingchild’spictureofahouse,madefromseverallines:Noticethatwehavebuiltthreedifferentsetsofjoined-uplines:onefortheoutlineofthehouse,andtwomore,oneforeachwindow.Consideringthebottom-leftdottobeat(0,0),theyare,infact,thesesetsoflines:forthehouseoutline(1,1)—(1,10)—(9,18)—(13,14)—(13,16)—(14,16)—(14,13)—(17,10)—(17,1)—(11,1)—(11,5)—(7,5)—(7,1)—(1,1)fortheleftwindow(3,10)—(6,10)—(6,7)—(3,7)—(3,10)fortherightwindow(12,10)—(15,10)—(15,7)—(12,7)—(12,10) #################### File: A%20MACHINE%20MADE%20THIS%20BOOK%20ten%20sketches%20of%20computer%20science%20-%20JOHN%20WHITINGTON%20%28PDF%29.pdf Page: 86 Context: # Chapter 6. Saving Space A common use for this sort of encoding is in the sending of faxes. A fax consists of a high-resolution black and white image. In this case, we are not compressing characters, but the black and white image of those characters itself. Take the following fragment:  This image is 37 pixels wide and 15 tall. Here it is with a grid superimposed to make it easier to count pixels: ``` | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | ``` We cannot compress the whole thing with Huffman encoding, since we do not know the frequencies at the outset—a fax is sent incrementally. One machine scans the document whilst the machine at the other end of the phone line prints the result as it pulls paper from its roll. It had to be this way because, when fax machines were in their infancy, computer memory was very expensive, so receiving and storing the whole image in one go and only then printing it was not practical. The solution the fax system uses is as follows. Instead of sending individual pixels, we send a line at a time, a list of runs. Each run is a length of white pixels or a length of black pixels. For example, a line of width 30 might contain 12 pixels of white, then 4 of black, then 2 of white, then 18 of black, and then 3 of white. We look up the code for each run and send the codes in order. To avoid the #################### File: A%20MACHINE%20MADE%20THIS%20BOOK%20ten%20sketches%20of%20computer%20science%20-%20JOHN%20WHITINGTON%20%28PDF%29.pdf Page: 115 Context: # Chapter 8. Grey Areas  is similar to a child cutting a potato to make a stamp – the wood is removed in areas where the artist does not want ink, and then ink is applied to the raised portions. Figure A shows a woodblock print *Der Formschnider* (The Blockcutter) from the *Panopticon omnia utilitarian mechanicarum* (Book of Trades), published in Germany in 1568. The detail achievable depends on the closeness of the grain of the wood, the properties of the ink and paper, and the permeability of the wood to ink. Attempts to produce areas which appear grey by using hatching or other patterns are likely to be either too coarse to be convincing, or they result in a solid inked area due to ink spreading across the surface of the block or along the fibres of the paper. The term *intaglio* (in-tah-lee-o), from the Italian *intagliare* – to engrave – refers to a group of techniques in which a metal plate has material removed manually, is rubbed with viscous ink all over, has the excess removed carefully with a cloth, and is then pressed onto a dampened piece of paper. The ink remains only in the lines engraved in the plate, and is transferred to the paper by the pressure of the press. Thus, the removal of material is normally done in the opposite sense to that in the woodblock process: we engrave where we want ink to be present, not where we want it to be absent. #################### File: A%20MACHINE%20MADE%20THIS%20BOOK%20ten%20sketches%20of%20computer%20science%20-%20JOHN%20WHITINGTON%20%28PDF%29.pdf Page: 84 Context: 70Chapter6.SavingSpacet00a01i10h11o000......Thereisaproblem,though.Itisveryeasytoencodeaword;forexample,“heat”encodesas1110100(thatis,11for“h”,1for“e”,01for“a”,and00for“t”).However,wecandecodeitinmanydifferentways.Thesequence1110100mightequallybetakentomean“eeespaceespace”or“hiispace”.Ourcodeisambiguous.Whatwerequireisacodewiththeso-calledprefixproperty–thatis,arrangedsuchthatnocodeinthetableisaprefixofanother.Forexample,wecannothaveboth001and0010ascodes,since001appearsatthebeginningof0010.Thispropertyallowsforunambiguousdecoding.Considerthefollowingalternativecode:space00e010t011a100i101h110o111......Thiscodeisunambiguous–nocodeisaprefixofanother.Theword“heat”encodesas110010100011andmaybedecodedun-ambiguously.Wecanhavethecomputerautomaticallycreateanappropriatecodeforourtext,takingintoaccountthefrequencies.Then,bysendingthecodetablealongwiththetext,weensureitmaybeunambiguouslydecoded.Hereisthefulltableofunam-biguouscodesforthefrequenciesderivedfromourtext:space111l10100,000100e100w00011.0101101t1011p110101k11000011a0111m110100j11000001i0110g110011T11000000 #################### File: A%20MACHINE%20MADE%20THIS%20BOOK%20ten%20sketches%20of%20computer%20science%20-%20JOHN%20WHITINGTON%20%28PDF%29.pdf Page: 159 Context: Chapter10.WordstoParagraphs145ProblemsSolutionsonpage166.Identifygoodhyphenationpointsinthefollowingwords:1.hyphenation2.fundraising3.arithmetic(noun)4.arithmetic(adjective)5.demonstration6.demonstrative7.genuine8.mountainous #################### File: A%20MACHINE%20MADE%20THIS%20BOOK%20ten%20sketches%20of%20computer%20science%20-%20JOHN%20WHITINGTON%20%28PDF%29.pdf Page: 25 Context: Chapter1.PuttingMarksonPaper11shapesneededtodrawgoodtypefaces,whichconsistnotonlyofstraightlines,butalsocurves. #################### File: A%20MACHINE%20MADE%20THIS%20BOOK%20ten%20sketches%20of%20computer%20science%20-%20JOHN%20WHITINGTON%20%28PDF%29.pdf Page: 63 Context: Chapter4.LookingandFinding49alwayshaveonecomparisoneachtime.Thetotal,then,isjustlW−lT+1(WetakeawaylTbecausewestopwhenthewordover-runstheendofthetext.)Inourexample,thatis29−6+1=24(forexample,searchingforzebras,since“z”willnevermatch).Intheworstcase,wehavetogoallthewaytothelastcharactertoseeifamatchoccurs(forexample,searchingfor“aaaaab”in“aaaaaaaaaaaaaaaaaaaaaaaaaaaaa”).Thenweneedsixcompar-isonsforeachposition,whichingeneralislW×(lW+lT+1),orinourcase6×(29−6+1)=6×24=144.CalculationssuchasthesearevitalinComputerScience.Wemustknowhowouralgo-rithmperformsasthesizeoftheproblemincreases.Thisalgorithmperformsreasonablywell:ifthetextsizedoubles,ittakestwiceaslong,justaswemightexpect.Thefieldofsearchingalgorithmsisvastandcomplex,butweshallconsideroneofthesimplerimprovements:skippingforwardmorethanoneplacewhenweknowforsomereasonthatamatchcannotnowhappen.Forexample,letusconsiderthefirstpositionagain:12T01234567890123456789012345678housesandhorsesandhearsesW012345horsesThe“h”matches,andthenthe“o”,butthe“r”intheworddoesnotmatchthe“u”inthetext.Sincethereisno“u”anywherein“horses”,wecanskipaheadtoposition3immediately:12T01234567890123456789012345678housesandhorsesandhearsesW012345horses3horsesLetusapplysuchskippingrulestoourwholesearch,andseehowmanycomparisonsarenowrequired.Lookatthediagramoverleaf.Weskippedtwotimes.Thefirsttimeasdescribedal-ready–thereisno“u”intheword“horses”.Thesecondtimewaswhenwefoundamatch:sincethereisno“h”anywhereelsein“horses”wemayskipsixplaces.Wehavereducedthenumberofcomparisonsfrom32to23. #################### File: A%20MACHINE%20MADE%20THIS%20BOOK%20ten%20sketches%20of%20computer%20science%20-%20JOHN%20WHITINGTON%20%28PDF%29.pdf Page: 7 Context: PrefaceItcanbetremendouslydifficultforanoutsidertounderstandwhycomputerscientistsareinterestedinComputerScience.Itiseasytoseethesenseofwonderoftheastrophysicist,oroftheevolutionarybiologistorzoologist.Wedon’tknowtoomuchaboutthemathe-matician,butweareinaweanyway.ButComputerScience?Well,wesupposeitmusthavetodowithcomputers,atleast.“Com-puterscienceisnomoreaboutcomputersthanastronomyisabouttelescopes”,thegreatDutchcomputerscientistEdsgerDijkstra(1930–2002),wrote.Thatistosay,thecomputerisourtoolforex-ploringthissubjectandforbuildingthingsinitsworld,butitisnottheworlditself.Thisbookmakesnoattemptatcompletenesswhatever.Itis,asthesubtitlesuggests,asetoflittlesketchesoftheuseofcomputersciencetoaddresstheproblemsofbookproduction.Bylookingfromdifferentanglesatinterestingchallengesandprettysolutions,wehopetogainsomeinsightintotheessenceofthething.Ihopethat,bytheend,youwillhavesomeunderstandingofwhythesethingsinterestcomputerscientistsand,perhaps,youwillfindthatsomeoftheminterestyou.vii #################### File: A%20MACHINE%20MADE%20THIS%20BOOK%20ten%20sketches%20of%20computer%20science%20-%20JOHN%20WHITINGTON%20%28PDF%29.pdf Page: 56 Context: 42Chapter4.LookingandFinding12T01234567890123456789012345678housesandhorsesandhearsesW012345horsesWehavecalledthetextTandthewordW.Noticethatwenumberupwardsfromzero,notone.Letusbeginbydescribingasimplesearchingmethodinthelarge,andthenrefineitintosmallersteps.Weshallbeansweringthequestion“Doesthewordappearinthetextand,ifso,where?”,andtheanswerwillbeaseriesofzero,one,ormorenumbersgivingthematchingpositions.Letuscomparepositions0to5inWwithpositions0to5inT.Plainly,theydonotallmatch,thoughsomeofthemdo.Position2differs(“r”inthewordWbut“u”inthetextT),andthisisenoughtodeclarefailure.Now,weshallshiftthewholewordWonwardonepositionandtryagain:12T01234567890123456789012345678housesandhorsesandhearsesW012345horsesHere,wefailoneverycharacterinourcomparison.Andwekeepfailingagainandagain,ateachpositionwetry,movingright-wardoneeachtime:12T01234567890123456789012345678housesandhorsesandhearsesW012345horsesFinally,though,wefindthematch(everycharacteristhesame),andwemaydeclarethatthewordWwasfoundatposition11inthetextT:12T01234567890123456789012345678housesandhorsesandhearsesW012345horses #################### File: A%20MACHINE%20MADE%20THIS%20BOOK%20ten%20sketches%20of%20computer%20science%20-%20JOHN%20WHITINGTON%20%28PDF%29.pdf Page: 52 Context: ```markdown # Chapter 3. Storing Words ## Braille Patterns The top section contains all those combinations using the top six dots only. (There were originally only six dots in Braille.) All the others then follow, for a total of 256. The patterns are not assigned particular letters, because these vary for each language: a pattern might represent the letter A in Western languages and something entirely different in Japanese or Vietnamese. Empty circles are used in most Braille typefaces so that, in patterns with only a few black dots, the empty circles can be felt with the finger to help distinguish between different characters. This is particularly useful when dealing with 8-dot patterns. | | 230 | 231 | 232 | 236 | 237 | 238 | 239 | 240 | 241 | 242 | 246 | 247 | 248 | 250 | 251 | 252 | |---|-----|-----|-----|-----|-----|-----|-----|-----|-----|-----|-----|-----|-----|-----|-----|-----| | 0 | | | | | | | | | | | | | | | | | | 1 | | | | | | | | | | | | | | | | | | 2 | | | | | | | | | | | | | | | | | | 3 | | | | | | | | | | | | | | | | | | 4 | | | | | | | | | | | | | | | | | | 5 | | | | | | | | | | | | | | | | | | 6 | | | | | | | | | | | | | | | | | | 7 | | | | | | | | | | | | | | | | | | 8 | | | | | | | | | | | | | | | | | | 9 | | | | | | | | | | | | | | | | | | A | | | | | | | | | | | | | | | | | | B | | | | | | | | | | | | | | | | | | C | | | | | | | | | | | | | | | | | | D | | | | | | | | | | | | | | | | | | E | | | | | | | | | | | | | | | | | | F | | | | | | | | | | | | | | | | | | G | | | | | | | | | | | | | | | | | | H | | | | | | | | | | | | | | | | | | I | | | | | | | | | | | | | | | | | | J | | | | | | | | | | | | | | | | | | K | | | | | | | | | | | | | | | | | | L | | | | | | | | | | | | | | | | | | M | | | | | | | | | | | | | | | | | | N | | | | | | | | | | | | | | | | | | O | | | | | | | | | | | | | | | | | | P | | | | | | | | | | | | | | | | | ``` #################### File: A%20MACHINE%20MADE%20THIS%20BOOK%20ten%20sketches%20of%20computer%20science%20-%20JOHN%20WHITINGTON%20%28PDF%29.pdf Page: 135 Context: Chapter8.GreyAreas121ProblemsSolutionsonpage163.Showthe17ditherpatternsgeneratedfromeachofthesegridsofnumbers.1.193111351574122101681462.191331657111286154141023.26111548913141073161251 #################### File: A%20MACHINE%20MADE%20THIS%20BOOK%20ten%20sketches%20of%20computer%20science%20-%20JOHN%20WHITINGTON%20%28PDF%29.pdf Page: 145 Context: Chapter9.OurTypeface131Palatino(LinotypePalatino Linotype : 1,328 glyphsGlyphs 0 to 449(cid:0) .ABCDEFGHIJKLMNOPQRSTUVWXYZÁÀÂÄÃĂÅǺĀĄÆǼĆĈČÇĊĎĐÐÉÈÊËĚĔĖĒĘǴĜĞĢĠĤĦÍÌÎÏĨĬİĪĮĴĶvĹĻĽzĿŁŃÑŇŅÅÓÒÔÖÕŎŐŌØǾŒŔŘŖêŚŜŠȘŞȚŤòŢŦÚÙÛÜŨŬŮŰŪŲẂẀŴẄÝỲŶŸŹŽŻƷŊ≤ÞabcdefghijklmnopqrstuvwxyzáàâäãăåǻāąæǽćĉčçċďđéèêëěĕėēęǵĝğģġĥħíìîïĩĭıīįĵķÛĸĺļľ¯ŀłńñňņʼn!óòôöõŏőōøǿœŕřŗ0śŝšșşțťţŧúùûüũŭůűūųẃẁŵẅýỳŷÿźžżʒŋþðßTIJVWXYZfiflffffiffl`abcdefghijſklmnoſtqrststvwªºⁿᵃᵇ}ᵈᵉÄᵍÇÉÑᵏÜᵐàᵒᵖãåçᵗᵘᵛëíìîïñó0123456789¢£§•¶ß®©™´¨≠ÆØ∞±≤≥¥µ⁰¹²³⁴⁵⁶⁷⁸⁹₀₁₂₃₄₅₆₇₈₉⁺⁻⁼⁽⁾₊₋₌₍₎‘’÷◊%‰⅟½⅓⅔¼¾⅕⅖⅗⅘⅙⅚⅛⅜⅝⅞ÍÎÏÌÓÔÒÚÛÙıˆ˜¯˘+±−÷×=≠≈<>Palatino,glyphs1–500 #################### File: A%20MACHINE%20MADE%20THIS%20BOOK%20ten%20sketches%20of%20computer%20science%20-%20JOHN%20WHITINGTON%20%28PDF%29.pdf Page: 91 Context: # Chapter 6. Saving Space  |  :--: | :--:  |  *Figure C*  |  :--: | :--:  |  *Figure D* #################### File: A%20MACHINE%20MADE%20THIS%20BOOK%20ten%20sketches%20of%20computer%20science%20-%20JOHN%20WHITINGTON%20%28PDF%29.pdf Page: 79 Context: Chapter6SavingSpaceAscomputersgeteverfaster,weaskevermoreofthem:ahigher-resolutionfilmstreamedinrealtime,afasterdownload,orthesameexperienceonamobiledeviceoveraslowconnectionaswehaveathomeorintheofficeoverafastone.Whenwetalkofefficiency,weareconcernedwiththetimetakentodoatask,thespacerequiredtostoredata,andknock-oneffectssuchashowoftenwehavetochargeourdevice’sbattery.Andsowecannotsimplysay“thingsaregettingfasterallthetime:weneednotworryaboutefficiency.”Animportanttoolforreducingthespaceinformationtakesup(andso,increasingthespeedwithwhichitcanbemovedaround)iscompression.Theideaistoprocesstheinformationinsuchaswaythatitbecomessmaller,butalsosothatitmaybedecompressed–thatistosay,theprocessmustbereversible.Imaginewewanttosendacoffeeorder.Insteadofwriting“Fourespressos,twodoubleespressos,acappuccino,andtwolattes”,wemightwrite“4E2DC2L”.Thisrelies,ofcourse,onthepersontowhomwearesendingtheorderknowinghowtodecompressit.Theinstructionsfordecompressingmightbelongerthanthemessageitself,butifwearesendingsimilarmessageseachday,weneedonlysharetheinstructionsonce.Wehavereducedthemessagefrom67charactersto7,makingitalmosttentimessmaller.Thissortofcompressionhappensroutinely,anditisreallyjustamatterofchoosingabetterrepresentationforstoringaparticularkindofinformation.Ittendstobemoresuccessfulthemoreuniformthedatais.Canwecomeupwithacompressionmethodwhichworksforanydata?Ifnot,whataboutonewhichworkswell65 #################### File: 15-MB-docx-file-download.pdf Page: 1 Context: # Boundary Waters Trip ![Boundary Waters Trip Map](https://via.placeholder.com/500x300.png?text=Boundary+Waters+Trip+"Day+1+to+Day+5+Routes+Map") Curabitur bibendum ante urna, sed blandit libero egestas id. Pellentesque rhoncus elit in lacus ultricies fringilla. Nam ac metus eu turpis mattis rhoncus. Mauris mattis sem ex, facilisis molestie sapien luctus non. Vestibulum tincidunt urna at odio suscipit, vel congue felis cursus. Etiam tellus magna, egestas ac suscipit in, laoreet quis felis. Proin non orci id dui tincidunt egestas. Vestibulum eleifend, ligula a scelerisque vehicula, risus justo ultricies ligula, et interdum lorem eu eget eu. Duis dignissim lacus vitae velit laoreet, vitae placaret velit aliquet. Etiam eget mollis nulla, ac vehicula mi. Etiam non sollicitudin velit, imperdiet commodo mi. Fusce quis tellus tellus. Donec dictum eulismod risus non tempus. Duis quis pellentesque nunc. Praesent elementum condimentum mollis. Phasellus dapibus quam a hendrerit placerat. Sed ultricies blandit nulla sed sodales. Nunc quis volutpat eros. Etiam bibendum eu tellus consequat blandit. Curabitur lacinia cursus diam sed pharetra. Proin molestie tristique mauris eu aliquam. Donec purus odio, molestie id suscipit sit amet, porttitor in erat. Vestibulum eu tellus vel lobortis porta nec elit tellus. Quisque pretium blandit dignissim. Proin eu metus convallis sapien efficitur mollis. Nunc luctus ex in nunc ornare, nec blandit orci faucibus. Aenean bibendum mi vel neque euismod hendrerit. Vestibulum ac pharetra magna. Ut rutrum, orci at blandit faucibus, justo mauris aliquet mauris, ut tempor lectus risus at ligula. Duis non tincidunt purus. Nam quis aliquam risus. Donec mattis convallis tempus. Fusce aliquam aliquet eros, nec rutrum lectus pretium a. Praesent blandit justo a mi dignissim placerat. Ut ullamcorper elit eget diam maximus luctus. In bibendum in massa eget facilisis. In iaculis lectus nec neque vehicula, ac molestie ante ornare. Sed sit amet sem mollis, egestas justo ac, rhoncus nunc. In in aliquam ante, non imperdiet ante. Mauris in sapien eu quam hendrerit mollis. Proin feugiat dignissim nisi, sed tincidunt ante aliquam et. Integer finibus est augue a tempus. Nullam facilisis quis nisl sit amet iaculis. Integer hendrerit metus in faucibus aliquet. Donec fermentum, lacus lobortis pulvinar vestibulum, felis ipsum auctor mi, ac pulvinar lacus magna. #################### File: A%20MACHINE%20MADE%20THIS%20BOOK%20ten%20sketches%20of%20computer%20science%20-%20JOHN%20WHITINGTON%20%28PDF%29.pdf Page: 185 Context: FurtherReading171Chapter6FundamentalDataCompressionIdaMengyiPu.PublishedbyButter-worth-Heinemann(2006).ISBN0750663103.TheFaxModemSourcebookAndrewMargolis.PublishedbyWiley(1995).ISBN0471950726.IntroductiontoDataCompressionKhalidSayood.PublishedbyMor-ganKaufmaninTheMorganKaufmannSeriesinMultimediaIn-formationandSystems(fourthedition,2012).ISBN0124157963.Chapter7PythonProgrammingfortheAbsoluteBeginnerMikeDawson.Pub-lishedbyCourseTechnologyPTR(thirdedition,2010).ISBN1435455002.OCamlfromtheVeryBeginningJohnWhitington.PublishedbyCo-herentPress(2013).ISBN0957671105.SevenLanguagesinSevenWeeks:APragmaticGuidetoLearningPro-grammingLanguagesBruceA.Tate.PublishedbyPragmaticBook-shelf(2010).ISBN193435659X.Chapter8HowtoIdentifyPrintsBamberGascgoine.PublishedbyThames&Hudson(secondedition,2004).ISBN0500284806.AHistoryofEngravingandEtchingArthurM.Hind.PublishedbyDoverPublications(1963).ISBN0486209547.PrintsandPrintmaking:AnIntroductiontotheHistoryandTechniquesAntonyGriffiths.PublishedbyUniversityofCaliforniaPress(1996).ISBN0520207149.DigitalHalftoningRobertUlichney.PublishedbyTheMITPress(1987).ISBN0262210096. #################### File: A%20MACHINE%20MADE%20THIS%20BOOK%20ten%20sketches%20of%20computer%20science%20-%20JOHN%20WHITINGTON%20%28PDF%29.pdf Page: 128 Context: # Chapter 8. Grey Areas   For colour images, several halftone screens are used, one for each of the primary printing colours used in the particular printing technology – often cyan, magenta, yellow, and black. The halftones are at different angles, so that the colours do not interfere with one another and the ink is more evenly distributed. Here is part of a glossy colour leaflet at 20x and 400x:   When we are producing a result for a type of device that has reasonably sharp or predictable dots (such as a computer monitor) and none of the vagaries of ink-flow, we can choose a more appropriate ordered dither, free of the need to build a spot as such, leading to the appearance of a higher resolution. Black and white computer displays are rather rare these days but were common in the past. Consider the following table and pattern for the 2x2 case: | | 2 | 3 | |---|---|---| | 4 | 1 | | - A pixel representation: - [ ] [ ] - [ ] [X] #################### File: A%20MACHINE%20MADE%20THIS%20BOOK%20ten%20sketches%20of%20computer%20science%20-%20JOHN%20WHITINGTON%20%28PDF%29.pdf Page: 62 Context: 48Chapter4.LookingandFinding12T01234567890123456789012345678housesandhorsesandhearsesW012345horses3horses1horses1horses1horses1horses1horses1horses1horses1horses1horses1horses6horses1horses1horses1horses1horses1horses1horses1horses1horses1horses1horses2FigureA #################### File: A%20MACHINE%20MADE%20THIS%20BOOK%20ten%20sketches%20of%20computer%20science%20-%20JOHN%20WHITINGTON%20%28PDF%29.pdf Page: 189 Context: Templates175Problem1.40246810121416182002468101214161820xy0246810121416182002468101214161820xy0246810121416182002468101214161820xy0246810121416182002468101214161820xy #################### File: A%20MACHINE%20MADE%20THIS%20BOOK%20ten%20sketches%20of%20computer%20science%20-%20JOHN%20WHITINGTON%20%28PDF%29.pdf Page: 83 Context: Chapter6.SavingSpace69Wearedownto880characters,areductionofabout10%com-paredwiththeoriginal.Thetop100wordsinEnglishareknowntocoverabouthalfoftheprintedwords,ingeneral.Wehavenotquiteachievedthatinthisexample.Letustrycountingthenumberofeachcharacterinourtexttoseeifwecantakeadvantageofthefactthatsomelettersaremorecommonthanothers(ourcurrentmethodmakesnouseofthefactthat,forexample,spacesareverycommon):167space30l10,120e24w8.71t19p5k62a19m4j55i19g4T51h19c3q49o18u2x45r15y1W42n13f1K41s13b1I33d10v1BThespacecharacterisbyfarthemostcommon(wesayithasthehighestfrequency).ThefrequenciesofthelowercaselettersareroughlywhatwemightexpectfromrecallingthevalueofScrabbletiles,thepunctuationcharactersareinfrequent,andthecapitallettersveryinfrequent.Wehavetalkedaboutwhatabitis,how8bitsmakeabyte,andhowonebyteissufficienttostoreacharacter(atleastinEnglish).Ouroriginalmessageis975bytes,or975×8=7800bits.Wecouldencodeeachofthe33characterswehavefoundinourtextusingadifferentpatternof6bits,since33islessthan64,whichisthenumberof6-bitcombinations000000,000001,...,111110,111111.(Thenumberof5-bitcombinationsis32,whichisnotquiteenough.)Thiswouldreduceourspaceto975×6=5850bits.However,wewouldhavewastedmuchofthepossiblesetofcodesandtakennoadvantageofourknowledgeofhowfrequentlyeachcharacteroccurs.Whatweshouldlikeisacodewhichusesshorterbitpat-ternsformorecommoncharacters,andlongerbitpatternsforlesscommonones.Letuswriteoutthebeginningsofsuchacode:space0e1 #################### File: 15-MB-docx-file-download.pdf Page: 4 Context: Praesent semper molestie dolor eget bibendum. Pellentesque ut nisi eros laoreet suscipit. Mauris lacinia rhoncus elit. Nullam id metus et eros rhoncus la blandit. Pellentesque massa augue, mollis eu dui eget, egestas ornare velit. Morbi ultrices nisl a lacinia commodo. Pellentesque faucibus purus ante, id vehicula arcu tincidunt ac. Orci varius natoque penatibus et magnis dis parturient montes, nascetur ridiculus mus. ## Ut libero massa Auctor et tortor ut, lacinia semper massa. Etiam a tortor turpis. Donec bibendum ipsum in laoreet euismod. Donec nec lectus purus. Praesent a porttitor lectus. Etiam cursus, ipsum ut maximus tincidunt, risus velit mattis felis, sed sodales odio leo volutpat sapien. Etiam a faucibus nunc. Ut magna elit, cursus a posuere ac, lobortis in orci. ## Nulla facilisi Sed sollicitudin dictum metus, vel dapibus magna accumsan ut. Nulla in laoreet velit. Lorem ipsum dolor sit amet, consectetur adipiscing elit. Morbi sit amet malesuada leo, non tincidunt augue. Curabitur venenatis bibendum rutrum. Vestibulum porta purus vel mattis dictum. Nam ac dictum justo. Mauris commodo, orci ut bibendum iaculis, elit nisi euismod leo, nec bibendum lectus lorem in purus. Mauris nec dictum mi, at dictum augue. Integer imperdiet sed nisi quis fermentum. ## Nullam libero justo Accumsan eget est, a rhoncus orci ante ligula. Mauris bibendum tempus consequat. Curabitur semper quis leo nec viverra. Pellentesque mollis placerat tincidunt. Etiam id ### Boundary Waters Trip - Day 1 - Day 2 - Day 3 - Day 4 - Day 5 - End Point Nisl a nisl elementum condimentum. Nunc non eleifend turpis, pulvinar eleifend purus. Cras sodales augue et libero consectetur iaculis in elit. In sed lectus rhoncus, sagittis sem eget, dignissim orci. Phasellus euismod augue nec sapien aliquam interdum. Sed iaculis in lacus eget tincidunt. Sed molestie, enim nec lobortis sagittis, tortor neque malesuada risus, nec molestie massa tortor non leo. Donec gravida vestibulum mauris, sed faucibus tortor consectetur id. Aliquam sit amet nulla ut orci porta venenatis. Vivamus posuere, metus pulvinar aliquam ullamcorper, dolor dui hendrerit metus, eget fermentum urna diam at nisl. #################### File: A%20MACHINE%20MADE%20THIS%20BOOK%20ten%20sketches%20of%20computer%20science%20-%20JOHN%20WHITINGTON%20%28PDF%29.pdf Page: 58 Context: 44Chapter4.LookingandFinding12T01234567890123456789012345678housesandhorsesandhearsesW012345horsesW012345horsesThatis,whenptisbetween0and23inclusive.So,wewritethisconditionintoourprogram,usingtheif,then,andlengthkeywords:definesearchptifpt+lengthW<=lengthTthen...123The<=symbolmeans“lessthanorequalto".Notethatthedots...atline3arenotpartoftheprogram.Theyjustshowthatwehavenotyetfilledinwhathappensifourconditionistrue.(Ifourconditionisnottrue,wedonothing,sincewehavefinishedsearching.)Wehaveindented(movedtotheright)line2bytwospacesaswell.Weuseindentationtoindicatestructureinourprogram.Nowtofillintherestofthesearchprocedure.Wewanttoperformthecomparisonofthewordwiththetextatthecurrentposition,andifitmatches,wewanttoprintoutthepositiononthescreen.definesearchptifpt+lengthW<=lengthTthenifcomparept0thenprintpt123Here,weareusingtheyet-to-be-concoctedcomparealgorithmtocomparethetextWwiththetextTatpositionpt.Ithasanotherparametertoo,whichitwilluseasacounter.Westartitoffatzero.Wedon’tneedtoknowhowcompareworksyet:justwhatitdoeswithwhatitisgiven.Thisconvenientblindnessiswhatallowsustoconstructprogramspiecebypieceinamodularfashion,replacingindividualpartswithoutchangingtheruleswhichconnectthem.Now,whetherornotwefoundamatch,itistimetomoveontothenextposition:werunsearchagain,addingonetothepositionpt: #################### File: A%20MACHINE%20MADE%20THIS%20BOOK%20ten%20sketches%20of%20computer%20science%20-%20JOHN%20WHITINGTON%20%28PDF%29.pdf Page: 21 Context: # Chapter 1. Putting Marks on Paper ## 7 Each column. For the line at exactly 45°, the two methods (row and column) produce the same result. Here is an illustration of the sorts of patterns of dots we see for lines of various slopes using this improved procedure:  This image is 100 dots tall and wide. The results are not terribly good, for two reasons. First, at low resolutions, the individual dots are clearly visible. Moreover, the density of the lines varies. A horizontal or vertical line of length 100 will have 100 dots over its length, but the 45° line has 100 dots over a length of about 141 (the diagonal of a square with sides of length 100 is √2 × 100), and so its density of dots is lower, and it appears less dark. When we are using a screen, rather than paper, to display our line, we can take advantage of the ability to use more than just black and white. And so, we can use varying shades of grey: dots which are right on the line are very dark grey, dots which are just close are lighter grey. Here is a line drawn in this manner, at three scales:  We can see that the line is smoother than would otherwise be the case. If you are reading this book on an electronic device, you may be able to see this effect on the text or images with a magnifying glass. Here is another example, with a more complex, filled shape, which might be used to represent an ampersand character:  #################### File: A%20MACHINE%20MADE%20THIS%20BOOK%20ten%20sketches%20of%20computer%20science%20-%20JOHN%20WHITINGTON%20%28PDF%29.pdf Page: 176 Context: 162Solutionsc)if(if1=2thenfalseelsetrue)then3else4=⇒iftruethen3else4=⇒35a)head[2,3,4]=⇒2b)tail[2]=⇒[]c)head[2,3,4]•[2,3,4]=⇒[2]•[2,3,4]=⇒[2,2,3,4]6a)[](firstif)b)[1](secondif)c)[1,3](via1•odds[]) #################### File: A%20MACHINE%20MADE%20THIS%20BOOK%20ten%20sketches%20of%20computer%20science%20-%20JOHN%20WHITINGTON%20%28PDF%29.pdf Page: 130 Context: # Chapter 8. Grey Areas | | | | | | |-----|-----|-----|-----|-----| | # | # | | # | # | | # | # | | # | # | | | | | | | | | | | | | This time, the results are rather better, due to the increased number of dot patterns, which allow a wider range of apparent shades of grey to be reproduced. Here is our camel and gradient built with the 4x4 patterns generated from our table:  The spots are, in general, much smaller than in the first set of patterns we looked at, and the gradient is reasonably convincing, although it does appear to be divided into little blocks. Figure K shows our camel picture using these sorts of small-dot dither patterns of sizes 2x2, 4x4, and 8x8. The difference is even more obvious when we use the gradient:  #################### File: A%20MACHINE%20MADE%20THIS%20BOOK%20ten%20sketches%20of%20computer%20science%20-%20JOHN%20WHITINGTON%20%28PDF%29.pdf Page: 77 Context: # Chapter 5. Typing it In We continue to build the first character by typing the next Zhuyin symbol: - ㄧ Now, we type in the tone using the number keys on the keyboard (there are four tones in Chinese, each a different variation on a given sound): - ㄣ We can now see the full character, which replaces the Zhuyin ones we typed in. It is the wrong character, but do not worry – this will correct itself once the system knows the end of the word. We begin on the second character: - 應 Now we type the second sound of the second character: - ㄗ #################### File: A%20MACHINE%20MADE%20THIS%20BOOK%20ten%20sketches%20of%20computer%20science%20-%20JOHN%20WHITINGTON%20%28PDF%29.pdf Page: 166 Context: 152Solutions2Wehave32rows:BitsNumberLetterBitsNumberLetter000000A1000016Q000011B1000117R000102C1001018S000113D1001119T001004E1010020U001015F1010121V001106G1011022W001117H1011123X010008I1100024Y010019J1100125Z0101010K1101026space0101111L1101127.0110012M1110028,0110113N1110129:0111014O1111030;0111115P1111131?Here,wechoosethecapitallettersandthepunctuationspace.,:;?andhopethiscoversmostusefulmessages.3Treasonisverymuchamatterofhabit,Smileydecided.48410410110911111410110510010111011610511610510111597109971101049711544116104101109111114101116104101121101120112114101115115116104101112101114115111110116104101121991111109910197108465a)Theloveofmoneyistherootof*all*evil. #################### File: A%20MACHINE%20MADE%20THIS%20BOOK%20ten%20sketches%20of%20computer%20science%20-%20JOHN%20WHITINGTON%20%28PDF%29.pdf Page: 142 Context: 128Chapter9.OurTypefaceThediagramshowsvariousalternativecharactersfor“d”and“g”intheZapfinotypeface.Youcanseethatsomesuitthewordmorethanothers.Inparticular,inthebottom-rightexample,theinitial“d”clashesawfullywiththenextletter.Beforecomputers,whentypewassetmanuallyusinglittlemetalpiecesarrangedintorows,smearedinink,andpressedontopaper,itwasnaturalforatypefacetohaveslightlydifferentglyphdesignsforeachsize.Aheadlinewouldhaveasubtlydifferentcharacterdesigntonormalsizedtext,andagaindifferenttothesortoftinytextusedforfootnotes.Partofthisisduetotheessentialopticalcharacteristicsofsmallshapes:itiseasiertoreadasmalltypefaceifithasproportionallywidercharactersthanitsnormalsize,forexample.Partofithastodowiththephysicalcharacteristicsoftheinkandpaper:inkspreads,andthewayitspreadsleadstothesamemetalshapeshowingdifferentlyatdifferentsizes.Whendesigningatypefacebycomputer,however,itistemptingtotakeashortcut:designthetypefaceonce,andthenautomaticallyscaleittowhateversizeisneededbysimplearithmeticonitscoordi-nates.Now,wehaveanysizeavailable,anddesigningthetypefaceischeaper.Thisshortcutwasnotavailabletothemetaltypeman-ufacturer.However,manygoodmoderncomputertypefacesstillhavemultipleso-calledopticalsizes.Theymayhaveseparateshapesfor5pt,8pt,10pt,12pt,and16pt,forexample.Wecanusethecom-puterscalingmethodinbetweensizes–toobtain11pt,forexample.FigureAontheoppositepageshowsaphraseprintedintheLatinModerntypeface,atfivedifferentsizes.Below,thesamephrasehasbeenrepeated,butscaleduptoshowthedifferencesclearly.WehavenotyetlookedattheotherthreefacesofthePalatinotypeface:theBold,theItalic,andtheBoldItalic.Aboldtypefaceisonewhichisthicker,usingmoreink.TheItalichasadifferent,slopingshape.Bothareusedforemphasis.YoucanseeBoldandItalicusedinvariousplacesinthisbook,butwedon’tuseBoldItalic.Thevariousshapesaredesignedtoworkcomfortablytogether.ShapeShapeShapeShape #################### File: A%20MACHINE%20MADE%20THIS%20BOOK%20ten%20sketches%20of%20computer%20science%20-%20JOHN%20WHITINGTON%20%28PDF%29.pdf Page: 156 Context: # Chapter 10. Words to Paragraphs We have shown the river with a line. Notice that the word "fermentum" appearing in almost the same place on two successive lines is also distracting. The problem is difficult to deal with automatically, and the text may have to be edited to fix it. The microtypographical techniques discussed above can help a little—since there are fewer widened spaces between words, the rivers will be narrower and less noticeable. You may wonder how type was set before computers. In much the same way, it turns out, but with many more manual steps and a lot of little pieces of metal. Here is one such piece, for the character “n” at a particular size, in a particular typeface: | Character | Description | |-----------|----------------------| | n | Body Shank | | ---- | Groove | | ---- | Foot | | ---- | Ratio | | ---- | Width | These are picked from a tray of boxes, by hand, and placed into rows in a composing stick, each row separated by little metal spaces, each row spaced by a metal strip (the leading). You can imagine that many many copies of these little metal pieces were required for each typeface and size, so it was an expensive business. Because it would eventually be used for printing by being inked and stamped or rolled on paper, the type is mirrored, and hard to read, and one must be careful not to mix up “p” and “q”, or “b” and “d”. (This is one possible origin of the phrase "mind your P's and Q's.") This painstaking process is shown on the opposite page. #################### File: A%20MACHINE%20MADE%20THIS%20BOOK%20ten%20sketches%20of%20computer%20science%20-%20JOHN%20WHITINGTON%20%28PDF%29.pdf Page: 61 Context: Chapter4.LookingandFinding47ofoursearchbygivingarunningcommentaryoftheparametersgiventosearchandcompare:W="horses"T="housesandhorsesandhearses"search0search9compare150compare00compare90search16compare11search10compare160search1compare100search17compare10search11compare170search2compare110search18compare20compare111compare180search3compare112search19compare30compare113compare190search4compare114search20compare40compare115compare200search511search21compare50search12compare210search6compare120search22compare60search13compare220search7compare130compare221compare70search14search23search8compare140compare230compare80search15Wecanseethat,mostofthetime,comparefailsonthefirstletterintheword,andweneedproceednofurther.Whenamatchisfound,everylettermustbechecked,ofcourse.Atpositions0and22wehadtocheckmorethanthefirstlettertoseethattherewasnomatch.Youcanrunthewholethingthroughonpaper,ifyouhavethepatience.Howmuchworkdidwehavetodotofindiftherewasamatch?Letusconsidercomparingtwolettersasourbasicunitofwork–howmanytimesdidwehavetodoit?ConsiderFigureAover-leaf.Wehavemadeatotalof32comparisons.(Thenumberofcomparisonsiswrittenattherightoneachline.)Wehavemadesurethatourcomparefunctionfailsassoonaspossible,buthavemadenootherefficiencies.Weareluckythat“h”doesnotappearinEnglishveryoften–ifoursearchwordbeganwith“e”wewouldhavetomakemanymoresecond-lettercomparisons.LetuscallthelengthofthewordlWandthelengthofthetextlT,andfindtheminimumandmaximumnumberofcomparisonsingeneral.Inthebestcase,thewordnevermatchesonthefirstletter,sowe #################### File: A%20MACHINE%20MADE%20THIS%20BOOK%20ten%20sketches%20of%20computer%20science%20-%20JOHN%20WHITINGTON%20%28PDF%29.pdf Page: 171 Context: ```markdown # Solutions | Colour | Length | Code | |--------|--------|--------| | Black | 9 | 000100 | | White | 3 | 1000 | | Black | 2 | 11 | | White | 37 | 0001010 | So we have: ``` 000101101011111100101011110000010 0110101000111110010100010101110001 0011000101101101001000110011001010 0101011111001000111101101010011011 0111101111100101110111011011100110 1110011000000001110010100000011101 0001000111111111100100001111111011 ``` ## The codes are: | Code | Length | Colour | Code | Length | Colour | |----------|--------|---------|----------|--------|---------| | 0001010 | 37 | White | 000100 | 9 | Black | | 0000111 | 1 | White | 0111 | 2 | White | | 000011 | 7 | Black | 11 | 2 | Black | | 000011 | 7 | Black | 10 | 3 | Black | | 1100 | 5 | White | 000011 | 1 | White | | 1000 | 3 | Black | 1100 | 5 | White | | 000010 | 9 | Black | 1110 | 6 | White | | 11 | 2 | Black | 11 | 2 | Black | | 1000 | 3 | Black | 10 | 3 | Black | | 0111 | 2 | White | 0000111 | 1 | White | ``` #################### File: A%20MACHINE%20MADE%20THIS%20BOOK%20ten%20sketches%20of%20computer%20science%20-%20JOHN%20WHITINGTON%20%28PDF%29.pdf Page: 46 Context: 32Chapter3.StoringWordsshiftingthepaperuponeline,sowemaybeginprintingthenext.Thespacecharacter32movesonespaceacross,withoutprintinganything.Mostoftheotherspecialcodesareofhistoricalinterestonly.WecanworkouttheASCIIcodestorepresentapieceoftextbylookingateachcharacterandfindingitsnumberinthetable.Considerthisquotation:"It'stheoldestquestionofallGeorge.Whocanspyonthespies?"--JohnLeCarre,"Tinker,Tailor,Soldier,Spy"NoticethatwedonothavetheacuteaccentfortheeinMrLeCarré’sname,andwehavetousetwodashes--tomakewhatwouldnormallybethe–longdash.TheremustbeaCarriageReturn,followedbyaLineFeedattheendofeachline,tomovetheprintingpositiontothebeginningofthenextline.Weobtainthefollowingsequenceofnumbers:"34l108s115T84I73space32p112i105t116G71i105n110’39e101e101n110s115o111s115k107space32r114?63e101t116g103"34r114h104e101cr13,44e101.46lf10space32space32cr13space32T84o111lf10space32a97l108space32space32i105d100w119-45l108e101h104-45o111s115o111space32r114t116space32J74,44space32c99o111space32q113a97h104S83u117n110n110o111e101space32space32l108s115s115L76d100t116p112e101i105i105y121space32e101o111space32C67r114n110o111a97,44space32n110r114space32o111space32r114S83 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124Chapter9.OurTypefaceInaddition,itcontainstheCyrilliccharactersusedinModernGreekaswellastheso-calledLatinonesweuseinEnglish.Herearethecapitallettersandlower-caselettersusedinEnglish.ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789(cid:362)(cid:363)(cid:364)(cid:365)(cid:366)(cid:367)(cid:368)(cid:369)(cid:370)(cid:371)IJ(cid:276)(cid:277)æœfiflffffiffl(cid:292)(cid:293)(cid:294)(cid:306)st(cid:308)(cid:309)(cid:278)(cid:279)(cid:280)(cid:107)ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789(cid:362)(cid:363)(cid:364)(cid:365)(cid:366)(cid:367)(cid:368)(cid:369)(cid:370)(cid:371)IJ(cid:276)(cid:277)æœfiflffffiffl(cid:292)(cid:293)(cid:294)(cid:306)st(cid:308)(cid:309)(cid:278)(cid:279)(cid:280)(cid:107)Then,twostylesofnumbers:theso-calledliningnumbers,whichhavethesameheightascapitalletters,andallsitonthebaseline,andtheoldstylenumbers,someofwhichhavedescenders,andarenotalltheheightofcapitalletters.ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789(cid:362)(cid:363)(cid:364)(cid:365)(cid:366)(cid:367)(cid:368)(cid:369)(cid:370)(cid:371)IJ(cid:276)(cid:277)æœfiflffffiffl(cid:292)(cid:293)(cid:294)(cid:306)st(cid:308)(cid:309)(cid:278)(cid:279)(cid:280)(cid:107)BelowaresomeoftheligaturesavailableinPalatino.Thesearespecialglyphsusedwhenletterswouldotherwisejoinunpleasantly,orinothersituationswheretwolettersshouldberepresentedbyasingleglyph.Somearefordecoration(suchas“Q”followedby“u”,whichisnormallyjustQu).Otherslooklikeligatures,butarereallyadifferentsoundorletter,adiphthong,suchasœ. #################### File: A%20MACHINE%20MADE%20THIS%20BOOK%20ten%20sketches%20of%20computer%20science%20-%20JOHN%20WHITINGTON%20%28PDF%29.pdf Page: 20 Context: 6Chapter1.PuttingMarksonPaperchoosethedotwhosecentreisclosesttothelineineachcase:012345670123xyAdmittedly,thisdoesnotlookmuchlikealine.Butifwechooseahigherresolutionforalineofthesameslope,andsodrawmoreandsmallerdots,weseeabetterapproximation:0510150246810xyNow,youmaywonderwhywechosetodrawonedotineachcolumninsteadofonedotineachrow.Forexample,insteadofputtingonedotineachofthecolumnsfromcolumn1tocolumn6,wemightputonedotineachoftherowsfromrow1torow3,againchoosingtheoneinthatrownearesttheactualline.Forthisshallowline,doingsowouldleadtoamostunpleasantresult:012345670123xyIfthelineissteeperthan45°,theconverseistrue(drawitonpapertosee).So,wechoosetoputoneblackdotineachrowinsteadofineachcolumninthiscase.Horizontalandverticallinesaresimplyspecialcasesofthisgeneralmethod–fortheverticalcasewedrawonedotineachrow;forthehorizontalcaseonedotin 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xiAcknowledgmentsThewordliston67isfromTheReadingTeacher’sBookofLists,FourthEdition(Fry,Kress&Fountoukidis),PrenticeHall,2000.TheliteraryquotationsusedasexampletextsinChapters3andtheproblemsinChapter6arefromJohnLeCarré’sTinker,Tailor,Soldier,Spy.ThetextinChapter6isfromFranzKafka’sTheTrial.LikewiseinChapter10fromhisMetamorphosis.ThehyphenationexamplesinChapter10arefromMicro-typographicextensionstotheTEXtypesettingsystem,thePhDThesisofHànTh´êThành,FacultyofInformatics,MasarykUniversity,Brno,October2000.ThecoverimageshowsaPaigeCompositor,courtesyoftheUnitedStatesPatentOffice.ThedrawingofFrenchCurvesonpage17wasmodifiedfromonecreatedbyJoshuaCertain.Thetablesonpages35–39appearbykindpermissionoftheUnicodeConsortium.UnicodeisaregisteredtrademarkofUnicode,Inc.intheUnitedStatesandothercountries.Thefacsimilepatentsonpages54,55,56,57,and59wereprovidedbytheUnitedStatesPatentandTrademarkOffice.ThepictureofaUnivackeyboardonpage60appearscourtesyoftheRetrocomputingSocietyofRhodeIsland.ThepictureofanIBMModelMkeyboardonpage60wastakenbySalCangeloso.Thewoodblockprintonpage101isDerFormschneider(TheBlockcutter)fromthePanopliaomniumilliberaliummechanicarum(BookofTrades);itwasprintedin1568andisintheBritishMuseum.Thepictureonpage102isadetailoftheengravingDerKreuzbrunnenzuMarienbadpublishedbyFranzSartoriin1819.TheengravingMelencoliaIbyAlbrechtDüreronpage103isheldattheMinneapolisInstituteofArt.Theimageofamezzotintplateonpage104wastakenbyDavidLadmore.ThepictureofthemezzotintprintbyFranzKrugeronpage105iscourtesyoftheImagePermanenceInstitute.TheRembrandtetchingTheHundredGuilderPrintonpage106isheldattheRijksmuseuminAmsterdam.Thephotographoffilmgrainonpage108wasprovidedbyKeithCooper.TheelectronmicroscopeimageoffilmgrainonthesamepageiscourtesyoftheUniversityofRochester.ThehalftonedpictureoftheSteinwayHallonEast14thStreetinManhattanonpage109isfromTheDailyGraphic,December2nd,1873.TheexamplesofZapfinoalternateglyphsonpage127arebasedontheinstructionsofDarioTaraborelli.ThetablesofPalatinoLinotypeonpages13 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Chapter4.LookingandFinding45definesearchptifpt+lengthW<=lengthTthenifcomparept0thenprintptsearch(pt+1)1234Notethat,duetotheindentation,bothlines3and4onlyhappeniftheifconditiononline2ismet.Now,seewhathappenswhenweexecuteourprogramonourexampleword“horses”andtext“horsesandhousesandhearses”:W="horses"T="housesandhorsesandhearses"search0search9search17search1search10search18search2search11search19search311search20search4search12search21search5search13search22search6search14search23search7search15search8search16Herewehaveshownnotonlythematchingpositionwhichourprogramprints,butasummaryoftheexecutionofourprogram,tohelpustounderstandwhatisgoingon.Amatchisfound–atposition11,asrequired–andtheprogramstopsafterposition23.Atleastforthisexample,ourprogramseemstowork.Runthroughitonpaperyourselftocheck.Nowtofillinthegap:wepretendedthatcomparealreadyexisted.Inreality,wewouldhavetowritesuchanalgorithm.Webeginbydefiningit,justlikeforsearch:definecompareptpw1Thecomparefunctionwilldifferfromthesearchoneinanimportantway:thesearchfunctionprintedthingstothescreen–thecomparealgorithmwillinsteadcalculateoneoftwospecialvalues:eithertrueorfalse.Thiswillbepassedbacktothesearchfunctionsoitcandecidewhattodo.Thecomparefunctionhastwoparameters:thesameoneassearchandonemore,pw,whichisthepositionintheword–wewillfirstcomparepositionptinthetextTwithpositionpwinthewordW,thenpt+1withpw+1etc.Rememberthatwhenwewrotesearch,westartedpwoffatzerowhenusingcompare.Assoonaswefindamismatch,westopand #################### File: A%20MACHINE%20MADE%20THIS%20BOOK%20ten%20sketches%20of%20computer%20science%20-%20JOHN%20WHITINGTON%20%28PDF%29.pdf Page: 35 Context: Chapter2.LetterForms21WehavedrawnthehalfwaypointsEandFonthelinesbetweentheend-pointsandcontrol-points,andthepointGhalfwaybetweenthecontrolpoints:Now,wedrawlinesbetweenEandG,andbetweenFandG,andfindthehalfwaypointsHandIonthoselines:ABCDEFGHIHalfwaybetweenthoseisthepointJ,whichisthemid-pointoftheoriginalcurve,andtheend-pointofbothnewcurveswearecreating:ABCDEFGHIJThetwofinalcurvescannowbeseen.Theyare,ontheleft,AEHJand,ontheright,JIFD: #################### File: A%20MACHINE%20MADE%20THIS%20BOOK%20ten%20sketches%20of%20computer%20science%20-%20JOHN%20WHITINGTON%20%28PDF%29.pdf Page: 131 Context: # Chapter 8. Grey Areas ## Figure K Small-spot ordered dithers with 2x2, 4x4, and 8x8 patterns.    #################### File: A%20MACHINE%20MADE%20THIS%20BOOK%20ten%20sketches%20of%20computer%20science%20-%20JOHN%20WHITINGTON%20%28PDF%29.pdf Page: 158 Context: # Chapter 10: Words to Paragraphs A galley, ready for printing:  Eventually, machines were developed to automatically place the pieces of type based on what was typed on a keyboard and to automatically justify each line. Such mechanical systems were in common use until the advent of so-called phototypesetting. This involved building an image by shining light through a series of stencils onto photosensitive paper, then photographing it. Computer typesetting supplanted both in the late twentieth century. #################### File: A%20MACHINE%20MADE%20THIS%20BOOK%20ten%20sketches%20of%20computer%20science%20-%20JOHN%20WHITINGTON%20%28PDF%29.pdf Page: 143 Context: Chapter9.OurTypeface129(cid:80)(cid:84)(cid:105)(cid:66)(cid:43)(cid:28)(cid:72)(cid:54)(cid:81)(cid:77)(cid:105)(cid:97)(cid:66)(cid:120)(cid:50)(cid:98)(cid:80)(cid:84)(cid:105)(cid:66)(cid:43)(cid:28)(cid:72)(cid:54)(cid:81)(cid:77)(cid:105)(cid:97)(cid:66)(cid:120)(cid:50)(cid:98)(cid:80)(cid:84)(cid:105)(cid:66)(cid:43)(cid:28)(cid:72)(cid:54)(cid:81)(cid:77)(cid:105)(cid:97)(cid:66)(cid:120)(cid:50)(cid:98)(cid:80)(cid:84)(cid:105)(cid:66)(cid:43)(cid:28)(cid:72)(cid:54)(cid:81)(cid:77)(cid:105)(cid:97)(cid:66)(cid:120)(cid:50)(cid:98)(cid:80)(cid:84)(cid:105)(cid:66)(cid:43)(cid:28)(cid:72)(cid:54)(cid:81)(cid:77)(cid:105)(cid:97)(cid:66)(cid:120)(cid:50)(cid:98)(cid:80)(cid:84)(cid:105)(cid:66)(cid:43)(cid:28)(cid:72)(cid:54)(cid:81)(cid:77)(cid:105)(cid:97)(cid:66)(cid:120)(cid:50)(cid:98)(cid:80)(cid:84)(cid:105)(cid:66)(cid:43)(cid:28)(cid:72)(cid:54)(cid:81)(cid:77)(cid:105)(cid:97)(cid:66)(cid:120)(cid:50)(cid:98)(cid:80)(cid:84)(cid:105)(cid:66)(cid:43)(cid:28)(cid:72)(cid:54)(cid:81)(cid:77)(cid:105)(cid:97)(cid:66)(cid:120)(cid:50)(cid:98)(cid:80)(cid:84)(cid:105)(cid:66)(cid:43)(cid:28)(cid:72)(cid:54)(cid:81)(cid:77)(cid:105)(cid:97)(cid:66)(cid:120)(cid:50)(cid:98)(cid:80)(cid:84)(cid:105)(cid:66)(cid:43)(cid:28)(cid:72)(cid:54)(cid:81)(cid:77)(cid:105)(cid:97)(cid:66)(cid:120)(cid:50)(cid:98)(cid:82)FigureAYoucanseethattheItalichasanentirelydifferentshapefromtheRoman.ThisisusualforseriftypefacessuchasPalatino.(Serifsarethelittlepiecesattachedtotheendofeachstrokeoftheletter.)However,forasansseriftypeface(onewithoutserifs),itissufficienttosimplyslanttheshapesbyfifteendegreesorso.Thiscanbedoneautomaticallybythecomputer,sothetypefacedesignerneedonlydesigntheRomanshapes.Unfortunately,automaticallyproducingaBoldfacefromaRomanoneisrathermoredifficult,soitisusuallydonemanually,albeitwithhelpfromcomputertools.Thisdiagramshowsanautomatically-generatedobliquefaceandaseparately-designeditalicface:Oblique ItalicOblique Italic #################### File: A%20MACHINE%20MADE%20THIS%20BOOK%20ten%20sketches%20of%20computer%20science%20-%20JOHN%20WHITINGTON%20%28PDF%29.pdf Page: 32 Context: 18Chapter2.LetterFormsNotethataBéziercurvemaybendonewayortwo,andthatitmayalsobestraight.Thedesignercanmovethecontrolpointsinteractivelytobuildawiderangeofcurvedlines.Ifyouhaveaccesstoaninteractivegraphicsprogramonyourcomputer,useittoplaywiththecontrolpointsofaBéziercurve.Thecurveswehavemadearestilltoosimpletobuildacom-plicatedshape,suchasourampersand.Tomakesuchshapes,westitchtogetheranumberofsuchcurves,makingsurethatanend-pointofonecurvecoincideswithanend-pointofthenext,formingachain.Asetofsuchchainsforourampersandisshownonthefollowingpage.Therearethreechainsofcurves,whichwecallpaths,intheampersand:oneforthemainpartandoneeachforthetwo“holes”.Thereare58curves,ofwhich5arestraightlines.Notethatseveralofthesecurvesjoinverysmoothlytooneanother.Thisisamatterofgettingthecontrolpointsforbothcurvesintherightplace:ifthecontrol-pointassociatedwiththeend-pointofonecurveisarrangedat180°tothecontrolpointassociatedwiththeend-pointofthenext,thejoinwillbesmooth,withnochangeinslopeatthatpoint.Otherwise,therewillbeadefinitecorner.Iftheend-pointsoftwoadjacentcurvesinthesequencedonotcoincideatall,therewillbeagap.(Wecallsuchcurvesdiscontinuous.)Onthefollowingpageareexamplesofdiscontinuous,continuous,andsmoothcontinuousBéziercurvepairs. 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Chapter7.DoingSums87=⇒4×(3×(iffalsethen1else2×factorial(2−1)))=⇒4×(3×(2×factorial(2−1)))=⇒4×(3×(2×factorial1))=⇒4×(3×(2×(if1=1then1else2×factorial(1−1))))=⇒4×(3×(2×(iftruethen1else2×factorial(1−1))))=⇒4×(3×(2×1))=⇒4×(3×2)=⇒4×6=⇒24Wesaidearlierthatwewantedtheexpressiontogetsmallereachstep.Thisisn’tthecasehere:werelaxthisrestrictiontosaysimplythatinaproperlyworkingprogramwithaproperinput,thecomputationeventuallyfinishes.Hereisthetreeforfactorial:factorialx=if...then...else×factorial−1xx1=1xConsideranothersimpletaskwithnumbers.Giventwonum-bersxandy,wewishtocalculatexy,whichispronounced“xtothepowery”.Thisisequaltoxmultipliedbyitselfytimes.So,forexample,25=2×2×2×2×2=32.Ontheotherhand,52=5×5=25.Notethatitisamathematicalconventionthatanynumbertothepower0is1.Thisfactallowsustobegintowritethepowerfunction(noticeithastwoinputs):powerxy=ify=0then1else... #################### File: A%20MACHINE%20MADE%20THIS%20BOOK%20ten%20sketches%20of%20computer%20science%20-%20JOHN%20WHITINGTON%20%28PDF%29.pdf Page: 109 Context: Chapter7.DoingSums956.Considerthisfunction,whichremoveselementsinpositions2,4,6...fromalist,leavingelementsinpositions1,3,5...oddsl=ifl=[]then[]elseiftaill=[]thenlelse[headl]•odds(tail(tailx))Evaluatethefollowingusesofthisfunction:a)odds[]b)odds[1,2]c)odds[1,2,3]Youneednotshowallthestagesofevaluation,ifyoucandoitinyourhead. #################### File: A%20MACHINE%20MADE%20THIS%20BOOK%20ten%20sketches%20of%20computer%20science%20-%20JOHN%20WHITINGTON%20%28PDF%29.pdf Page: 17 Context: # Chapter 1. Putting Marks on Paper be reading this as a physical paperback book, printed and bound by very expensive equipment. You may be reading it as an electronic document (such as a PDF file) on your computer, tablet, or smartphone. Or, you may be reading it on some sort of special-purpose eBook reader. Each of these scenarios has different characteristics. Every page of the printed book is made up of hundreds of millions of little dots, each of which may be white (no ink) or black (ink). We cannot typically see the dots with the naked eye. The number of dots is known as the **resolution** (from the word "resolve"). A low resolution image is one where it is easy for the eye to resolve (that is, distinguish) the individual dots. A high-resolution image has dots so small and tightly packed that the naked eye cannot distinguish them. A high-resolution printer, such as the one printing the physical copy of this book, may have as many as 600 or 1200 dots per inch (dpi); that is to say, between 600 × 600 = 360,000 and 1200 × 1200 = 1,440,000 dots per square inch. The screen of a computer or tablet may only have 100 to 300 dpi, but it can display many shades of grey and colours. If the resolution is too low, we see blocky images. Here is a part of a capital letter A in black and white at 60 dpi, 30 dpi, and 15 dpi: ``` A ``` We have used square dots here, as may be used on a modern computer screen (we call them **pixels**, which is short for "picture elements"). For viewing a page on a typical computer viewer, we might have a book 2018 × 1536 = 5,193,728 dots on the whole screen, but they may be colours or greys, as well as black or white. When printing a book like this, we have many more dots, but only black ink. Let us say, for example, that we have a US Letter page (8.5 inches by 11 inches) and we are printing at a resolution of 1200 dpi. We have 1200 × 1200 = 1,440,000 dots per square inch, so we have 1200 × 8.5 × 11, or 134,640,000 dots on the page, each of which may be black or white. Here are some photographs, taken under a microscope, of lettering as it appears in high-quality printing, and on the next lower quality, cheaper newsprint used for the daily newspaper: #################### File: A%20MACHINE%20MADE%20THIS%20BOOK%20ten%20sketches%20of%20computer%20science%20-%20JOHN%20WHITINGTON%20%28PDF%29.pdf Page: 99 Context: Chapter7.DoingSums85(Thisisonlysomewhatrelatedtotheif...then...elsecon-structofChapter4–pleaseputitoutofyourmind.)Asamathe-maticalconstruct,thislooksratherstrange:weareusedtoseeingoperatorslike+and×,whichconsistofonesymbolandhaveanoperandeitherside.Thisnewoperatorhasthreeparts(if,then,andelse)andthreeoperands(x=4,0,andx+1),andtheyarespreadallovertheplace!Butifwewriteitoutasatree,itlooksmuchliketheearliertrees:if...then...else+1x0=4xAnoperatorhavingmorethantwooperandsisnotsostrangeafterall.Supposeweevaluateitintheenvironmentwherex=6:if...then...else+160=46=⇒if...then...else+160false=⇒+16=⇒7Ofcourse,wecanwritethisoutinlinearform:if6=4then0else6+1=⇒iffalsethen0else6+1=⇒6+1=⇒7And,wecannamethefunction:testl=ifx=4then0elsex+1Wearegettingalittleclosertothesortsofcalculationsarealprogramdoes:makingdecisionsaboutwhichpartofanexpression ########## """QUERY: Please summarize the whole context. It is important that you include a summary for each file. All files should be included, so please make sure to go through the entire context""" Consider the chat history for relevant information. If query is already asked in the history double check the correctness of your answer and maybe correct your previous mistake. If you find information separated by a | in the context, it is a table formatted in Markdown - the whole context is formatted as md structure. If the client ask for a formatting structure follow his advise. Final Files Sources: A%20MACHINE%20MADE%20THIS%20BOOK%20ten%20sketches%20of%20computer%20science%20-%20JOHN%20WHITINGTON%20%28PDF%29.pdf - Page 82, 15-MB-docx-file-download.pdf - Page 6, A%20MACHINE%20MADE%20THIS%20BOOK%20ten%20sketches%20of%20computer%20science%20-%20JOHN%20WHITINGTON%20%28PDF%29.pdf - Page 117, A%20MACHINE%20MADE%20THIS%20BOOK%20ten%20sketches%20of%20computer%20science%20-%20JOHN%20WHITINGTON%20%28PDF%29.pdf - Page 80, A%20MACHINE%20MADE%20THIS%20BOOK%20ten%20sketches%20of%20computer%20science%20-%20JOHN%20WHITINGTON%20%28PDF%29.pdf - Page 149, A%20MACHINE%20MADE%20THIS%20BOOK%20ten%20sketches%20of%20computer%20science%20-%20JOHN%20WHITINGTON%20%28PDF%29.pdf - Page 153, 15-MB-docx-file-download.pdf - Page 10, A%20MACHINE%20MADE%20THIS%20BOOK%20ten%20sketches%20of%20computer%20science%20-%20JOHN%20WHITINGTON%20%28PDF%29.pdf - Page 66, A%20MACHINE%20MADE%20THIS%20BOOK%20ten%20sketches%20of%20computer%20science%20-%20JOHN%20WHITINGTON%20%28PDF%29.pdf - Page 187, A%20MACHINE%20MADE%20THIS%20BOOK%20ten%20sketches%20of%20computer%20science%20-%20JOHN%20WHITINGTON%20%28PDF%29.pdf - 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Page 11, A%20MACHINE%20MADE%20THIS%20BOOK%20ten%20sketches%20of%20computer%20science%20-%20JOHN%20WHITINGTON%20%28PDF%29.pdf - Page 59, A%20MACHINE%20MADE%20THIS%20BOOK%20ten%20sketches%20of%20computer%20science%20-%20JOHN%20WHITINGTON%20%28PDF%29.pdf - Page 35, A%20MACHINE%20MADE%20THIS%20BOOK%20ten%20sketches%20of%20computer%20science%20-%20JOHN%20WHITINGTON%20%28PDF%29.pdf - Page 131, A%20MACHINE%20MADE%20THIS%20BOOK%20ten%20sketches%20of%20computer%20science%20-%20JOHN%20WHITINGTON%20%28PDF%29.pdf - Page 158, A%20MACHINE%20MADE%20THIS%20BOOK%20ten%20sketches%20of%20computer%20science%20-%20JOHN%20WHITINGTON%20%28PDF%29.pdf - Page 143, A%20MACHINE%20MADE%20THIS%20BOOK%20ten%20sketches%20of%20computer%20science%20-%20JOHN%20WHITINGTON%20%28PDF%29.pdf - Page 32, A%20MACHINE%20MADE%20THIS%20BOOK%20ten%20sketches%20of%20computer%20science%20-%20JOHN%20WHITINGTON%20%28PDF%29.pdf - Page 101, A%20MACHINE%20MADE%20THIS%20BOOK%20ten%20sketches%20of%20computer%20science%20-%20JOHN%20WHITINGTON%20%28PDF%29.pdf - Page 109, A%20MACHINE%20MADE%20THIS%20BOOK%20ten%20sketches%20of%20computer%20science%20-%20JOHN%20WHITINGTON%20%28PDF%29.pdf - Page 17, A%20MACHINE%20MADE%20THIS%20BOOK%20ten%20sketches%20of%20computer%20science%20-%20JOHN%20WHITINGTON%20%28PDF%29.pdf - Page 99 ================================================== **Elapsed Time: 9.67 seconds** ================================================== FINAL ANSWER Answer: The provided text is a collection of excerpts from a book titled "A MACHINE MADE THIS BOOK: ten sketches of computer science" by John Whitington. The book explores various aspects of computer science through the lens of book production. Here's a summary of each file: **File: A MACHINE MADE THIS BOOK ten sketches of computer science - JOHN WHITINGTON (PDF).pdf** This file contains excerpts from various chapters of the book. It covers topics like: * **Chapter 1: Putting Marks on Paper:** Discusses the basics of representing shapes and lines using dots on paper or a computer screen. * **Chapter 2: Letter Forms:** Explores how to draw letters using Bézier curves and how to combine them into shapes. * **Chapter 3: Storing Words:** Explains how computers store and represent text, including different encoding systems like ASCII and Unicode. * **Chapter 4: Looking and Finding:** Introduces the concept of algorithms and how they can be used to search for words in text. * **Chapter 5: Typing it In:** Discusses how different languages are typed into computers, including the challenges of representing Asian languages. * **Chapter 6: Saving Space:** Explores compression techniques for reducing the size of text and images without losing information. * **Chapter 7: Doing Sums:** Introduces basic programming concepts, including how to write functions to perform calculations and manipulate lists. * **Chapter 8: Grey Areas:** Discusses the challenges of reproducing grey tones in printing, exploring historical and modern methods. * **Chapter 9: Our Typeface:** Investigates the Palatino typeface and its various features, including metrics, kerning, and ligatures. * **Chapter 10: Words to Paragraphs:** Explains how lines of text are combined into paragraphs and how to format them for printing. **File: 15-MB-docx-file-download.pdf** This file is a document about a Boundary Waters Trip. It includes: * **Overview:** A brief description of the trip. * **Key Features:** Highlights of the trip. * **Additional Information:** Details about the trip, including a list of days and an end point. The book "A MACHINE MADE THIS BOOK" uses a conversational and engaging style to explain complex computer science concepts. It provides a unique perspective on the subject by connecting it to the practical world of book production. ================================================== **Elapsed Time: 0.45 seconds** ==================================================