explain xkcd - User contributions [en]

Talk:1685: Patch

2016-05-26T22:26:52Z

141.101.80.121: /* Resemblance to Xerox number mangling issue */

Hey, I'm first! Guessing the Bot only JUST created this, it was mere minutes after midnight EST when I landed on this page. Unfortunately this is a comic I'm less capable of explaining. From the looks of it, his Photoshop Patch turned what looks like C code into gobbledegook by filling in several of the spaces (and I think even changing some of the characters, possible with characters which fill more of the space). - NiceGuy1 [[Special:Contributions/108.162.218.77|108.162.218.77]] 04:24, 25 May 2016 (UTC)

This appears to be Python code. Note the "def" keyword, how "for i in [garbled]:" is used rather than C's for syntax, and how there are no semicolons or braces. --[[User:Sherlock9|Sherlock9]] ([[User talk:Sherlock9|talk]]) 05:03, 25 May 2016 (UTC)

Photoshop has a 'patch' tool but it has a very different function from a software patch. {{unsigned ip|108.162.242.123}}
:An explanation of Photoshop's patch tool might be helpful in identifying patterns in what pixels were changed by it, perhaps facilitating the identification of some likely characters. [[User:Dansiman|Dansiman]] ([[User talk:Dansiman|talk]]) 05:56, 25 May 2016 (UTC)

The first function looks like "isPrime" and seems to check if a number is prime. The last function looks like "quicksort". Both are common functions you create when learning programming. Not sure about the second one, but it looks like it uses regular expressions. -- [[Special:Contributions/198.41.242.242|198.41.242.242]] 06:44, 25 May 2016 (UTC)
:I think the second one is "isPrimeRegex". *cringe* [[Special:Contributions/141.101.104.25|141.101.104.25]] 08:55, 25 May 2016 (UTC)

Second function looks like a function to check if number is a prime using Regex (described here http://www.noulakaz.net/2007/03/18/a-regular-expression-to-check-for-prime-numbers/). I don't know if it deserves some special mention, but at least to me (non-programmer) it looks like one of the most arcane things you can do in programming [[Special:Contributions/141.101.80.79|141.101.80.79]] 07:22, 25 May 2016 (UTC)
:That indeed looks very much like it. I think this is worth mentioning. --[[Special:Contributions/198.41.242.240|198.41.242.240]] 11:22, 25 May 2016 (UTC)
:Note that mathematically speaking, that regular expression is NOT regular expression - use of backreference in match is one of originally perl extension which makes it much more powerful (and much slower in some cases). It's just that both python and ruby already copied most of perl extensions of regular expressions. -- [[User:Hkmaly|Hkmaly]] ([[User talk:Hkmaly|talk]]) 12:39, 25 May 2016 (UTC)

Do you think the use of pi is a reference to one of the other comics(I forgot which one...)?[[User:Transuranium|Transuranium]] ([[User talk:Transuranium|talk]]) 10:35, 25 May 2016 (UTC)Transuranium
:I rather guess it is short for pivot. See {{w|quicksort}} for what the pivot does. --[[Special:Contributions/198.41.242.240|198.41.242.240]] 11:22, 25 May 2016 (UTC)

You know, it's theoretically possible for Photoshop to create compilable code in [https://esolangs.org/wiki/Piet the esoteric programming language] "[http://www.dangermouse.net/esoteric/piet.html Piet]". But unless there's a way to turn off the Patch tool's antialiasing, it'll be practically impossible for patches larger than a single pixel. [[Special:Contributions/108.162.237.220|108.162.237.220]] 14:15, 25 May 2016 (UTC)

I don't really know anything about programming, but it looks like it's checking for factors of n from 2 to sqrt(n)+1. Why would it need to check any number larger than sqrt(n) though? If i>sqrt(n), then ij=n implies that j<sqrt(n), and j should already have been found. So the largest integer you need to check is floor( sqrt(n) ), which is in the range from 2 to sqrt(n). Checking ceiling( sqrt(n) ) for a non-square number seems redundant. [[Special:Contributions/108.162.237.250|108.162.237.250]] 15:25, 25 May 2016 (UTC)
:It's because <code>range(a, b)</code> in Python means the interval [a, b) (excluding b). [[Special:Contributions/108.162.222.29|108.162.222.29]] 15:41, 25 May 2016 (UTC)
::That mismatched bracket in your comment is hurting me. [[Special:Contributions/162.158.68.71|162.158.68.71]] 17:02, 25 May 2016 (UTC)
:: It's not mismatched; the right paren indicates the value's the upper limit but excluded. I'd include a right bracket in my response but I think that might make a compiler curse. [[User:Elvenivle|Elvenivle]] ([[User talk:Elvenivle|talk]])

The line with re.match in the likely original code should have an "r" for "raw" before the first string thus:
if re.match(r'^1?$|^(11+?)\1+$', '1'*n):
I am not changing it in the main explanation because I don't know what colour it should be and it's my first time contributing. - Charles W. [[Special:Contributions/141.101.98.42|141.101.98.42]] 22:24, 25 May 2016 (UTC)
:Seems like it has been changed by now. --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 07:13, 26 May 2016 (UTC)

Has someone added this to the Protip category?[[Special:Contributions/162.158.2.139|162.158.2.139]] 23:53, 25 May 2016 (UTC)
:Uhm yes, it should be clear right below these comment on the main page? All categories are listed at the bottom of each page. --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 07:01, 26 May 2016 (UTC)

It might be worth explaining the [pivot] * (len(a) - (len(l) + len(r))) since that threw me when I first saw it. Since l has the elements of a < pivot, and r has the elements of a > pivot, len(a) - (len(l) + len(r)) will be the number of elements in a that = pivot (which must be in the range [1, len(a)]), and these are then 'spliced' into the result between the result of quicksorting l and r.
[[User:Jstout|Jstout]] ([[User talk:Jstout|talk]]) 19:48, 26 May 2016 (UTC)

== Resemblance to Xerox number mangling issue ==

To me, this reminds me of the problem that a large set of Xerox copiers had. Their faulty use of image compression when scanning could cause portions of images to be replaced with similar portions, but the threshold of similarity was loose enough that numeric data would be subtly corrupted. For example, building plans and spreadsheet data could have numbers copied incorrectly, either of which could certainly have disastrous consequences. Documents were corrupted for a period as much as eight years before the problem was corrected, making legal archive data unreliable for this period, and some of the faulty machines may still be in use. http://www.dkriesel.com/en/blog/2013/0802_xerox-workcentres_are_switching_written_numbers_when_scanning
:Now that you mention it... Although here it's a person intentionally doing harm to the image.[[Special:Contributions/173.245.52.69|173.245.52.69]] 22:20, 26 May 2016 (UTC)
::So ''that's'' what it was! I wondered why all the copies I could find of ''Concrete Mathematics'' had random font changes all over (and half the formulas came out wrong). [[Special:Contributions/141.101.80.121|141.101.80.121]] 22:26, 26 May 2016 (UTC)

1491: Stories of the Past and Future

2015-02-25T18:46:46Z

141.101.80.121: /* Trivia */ FTGJ

{{comic
| number = 1491
| date = February 25, 2015
| title = Stories of the Past and Future
| image = stories_of_the_past_and_future.png
| titletext = Little-known fact: The 'Dawn of Man' opening sequence in 2001 cuts away seconds before the Flinstones theme becomes recognizable.
}}

==Explanation==
{{incomplete|Created by a BOT - Please change this comment when editing this page.}}
''A larger version of the image is available [http://xkcd.com/1491/large/ here].''

X-axis: Date of publication.

Y-axis, "Years in the future": Number of years the story's events take place, after the story's publication.

Y-axis, "Years in the past": Number of years the story's events take place, before the story's publication.

For example, "Water Margin" was published in the 14th century (x ~= 1300) and relates events from the 12th century, about 200 years before its publication (y ~= 200 in the past).

Another example: The film ''{{w|The Bridge on the River Kwai}}'' was released in 1957 and it was set around 14 years before (~1942-43).

Grey area in the "Years in the future" part: Stories set in the future (from their publication's date), whose the story's events' date is already past (from now).

Grey area in the "Years in the past" part: Stories set in the past (from their publication's date), published closer to their setting than to today.

Taking the "years in the past" on the y-axis to be read as negatives like in most graphs one can write:

Dates on the lower line satisfy: y = x-2015. Corresponding works were published in the year x = 2015+y and are set in the year x+y = 2015+2y.

Dates on the upper line satisfy: y = 2015-x. Corresponding works were published in the year x = 2015-y and are set in the year x+y = 2015.

Thus it's clear that the definitions of the lines are consistent with each other as they follow similar but inverted functions.

In the top portion of the graph, the two sides of the line are defined as "still possible" and "obsolete" (gray area). The gray area (obsolete) expands over time, the prediction (or science fiction work) that are not confirmed by reality are doomed to be obsolete. The author mark the line of the stories set in 2015; they are the expectation for our present in different past times.

In the bottom graph, the line indicates the limit in which the publishing time is nearer to the time treated in the work than to the present. The work in the gray area could be perceived as written by contemporary writers while in most cases they refer to a further past. This is expressed in the warning: "Modern audiences may not recognize which part were supposed to sound old". This is a recurrent theme in the author's work, being already formulated in [[Period_Speech]].

The bottom of the chart has the Star Wars films, which are set "A long time ago".

===Works listed===

{| {{table}}
| align="center" style="background:#f0f0f0;"|'''Publication'''
| align="center" style="background:#f0f0f0;"|'''Description'''
| align="center" style="background:#f0f0f0;"|'''Year Written'''
| align="center" style="background:#f0f0f0;"|'''Year Difference'''
| align="center" style="background:#f0f0f0;"|'''Year Set In'''
|-
| [[Wikipedia:Memoirs of the Twentieth Century|Memoirs of the Twentieth Century]]|| book written by Samuel Madden||1733||264||1997
|-
| [[Wikipedia:Golf in the Year 2000|Golf in the Year 2000]]|| novel written by J. McCullough||1892||108||2000
|-
| [[Wikipedia:Looking Backward|Looking Backward]]|| novel written by Edward Bellamy||1888||112||2000
|-
| [[Wikipedia:Enoch Soames|Enoch Soames]]|| short story by Max Beerbohm||1897||100||1997
|-
| [[Wikipedia:The Time Machine|The Time Machine]]|| novel written by H.G. Wells||1895||800,806||802,701
|-
| [[Wikipedia:Nineteen Eighty-Four|1984]]||novel written by George Orwell||1949||35||1984
|-
| [[Wikipedia:Wythnos yng Nghymru Fydd|A Week in the Wales of the Future]]||novel written by Islwyn Ffowc Elis||1957||76||2033
|-
| [[Wikipedia:The Jetsons|The Jetsons]]||TV series produced by Hanna-Barbera||1962 *||100||2062 †
|-
| [[Wikipedia:Star Trek: The Original Series|Star Trek !TOS!]]||TV series created by Gene Roddenberry||1966 *||298||2264
|-
| [[Wikipedia:2001: A Space Odyssey (film)|2001: A Space Odyssey]]||novel written by Arthur C. Clarke||1968||33||2001
|-
| [[Wikipedia:Space: 1999|Space: 1999]]||TV series created by Gerry and Sylvia Anderson||1975 *||24||1999
|-
| [[Wikipedia:2010: Odyssey Two|2010: Odyssey Two]]||novel written by Arthur C. Clarke||1982||28||2010
|-
| [[Wikipedia:Star Trek: The Next Generation|Star Trek: The Next Generation]]||TV series created by Gene Roddenberry||1987 *||377||2364
|-
| [[Wikipedia:2061: Odyssey Three|2061: Odyssey Three]]||novel written by Arthur C. Clarke||1987||74||2061
|-
| [[Wikipedia:Zero Wing|Zero Wing]]||arcade/computer game||1989||112||2101 (previously referenced in [[887: Future Timeline]])
|-
| [[Wikipedia:3001: The Final Odyssey|3001: The Final Odyssey]]||novel written by Arthur C. Clarke||1997||1004||3001
|-
| [[Wikipedia:Star Trek: Enterprise|Enterprise]]||TV series||2001 *||150||2151
|-
| [[Wikipedia:Back to the Future Part II|Back to the Future Part II]]||film directed by Robert Zemeckis||1989||26||2015
|-
| [[Wikipedia:The Transformers (TV series)|Transformers (TV Series)]]||TV series||1984 *||~ 20||< 2010
|-
| [[Wikipedia:Terminator 2: Judgment Day|Terminator 2 (1995 Portion)]]||film directed by James Cameron||1991||4||1995
|-
| [[Wikipedia:Casablanca (film)|Casablanca]]||film directed by Michael Curtiz||1942||< 1||1941
|-
| [[Wikipedia:The Pillow Book|The Pillow Book]]||book written by Sei Shōnagon||1002||6||996
|-
| [[Wikipedia:History of the Peloponnesian War|History of the Peloponnesian War]]||history written by Thucydides||~400 BCE||~10||431-411 BCE
|-
| Moby Dick||||||||
|-
| Gospels||||||||
|-
| The Epic of Gilgamesh||||||||
|-
| The Iliad||||||||
|-
| Ashokavadana||||||||
|-
| Book of Genesis||||||||
|-
| Water Margin||||||||
|-
| King John||||||||
|-
| Henry IV||||||||
|-
| Richard III||||||||
|-
| Henry VIII||||||||
|-
| Julius Caesar||||||||
|-
| King Lear||||||||
|-
| A Conneticut Yankee in King Arthur's Court||||||||
|-
| [[wikipedia:Lest Darkness Fall|Lest Darkness Fall]]||alternate history SF novel||1939||1404||535
|-
| Asterix||French comic by Goscinny and Uderzo||1959*||2009||50 B.C.
|-
| The Ten Commandments||film by Cecil B. DeMille||1956||3412||[[wikipedia:The Exodus#Date|1446 BCE]]
|-
| The Flintstones||TV series produced by Hanna-Barbera||1960*||>2,5 million||Stone Age
|-
| 2001: A Space Odyssey (prologue)||novel written by Arthur C. Clarke||1968|||>2,5 million||Stone Age ([[wikipedia:Lower Paleolithic|Lower Paleolithic]])|
|-
| Star Wars (IV - VI)||original film trilogy ||1977-1983|| ||A long time ago
|-
| Star Wars (I - III)||prequel film trilogy||1999-2005|| ||A long time ago
|-
| Raptor Red||novel by Robert Bakker||1995||>65 million||Cretaceous Period
|-
| Star Wars (VII - IX)||sequel film trilogy||2015-2021|| ||A long time ago
|-
| Ice Age||animated films by Blue Sky Studios||2002*||>12,000||[[wikipedia:Last glacial period| Paleolithic-Mesolithic]]
|-
| 10,000 BC||film by Roland Emmerich||2008||11,992||10,000 BC
|-
| 300||film by Zack Snyder||2007||2487||[[wikipedia:Battle of Thermopylae|480 BC]]
|-
| Year One||film by Harold Ramis||2009||2008||1 AD
|-
| The Prince of Egypt||animated film by DreamWorks||1998||3412||[[wikipedia:The Exodus#Date|1446 BCE]]
|-
| Downton Abbey||||||||
|-
| Pearl Harbour||film by Michael Bay||2001||60||1941
|-
| Saving Private Ryan||film by Steven Spielberg||1998||54||1944
|-
| Chariots of Fire||film by Hugh Hudson||1981||57||1924
|-
| Blazing Saddles||film by Mel Brooks||1974||100||1874
|-
| Back to the Future Part III||film by Robert Zemeckis||1990||105||1885
|-
| Roots||||||||
|-
| Treasure Island||||||||
|-
| The Last of the Mohicans||||||||
|-
| A Tale of Two Cities||||||||
|-
| Gone With The Wind||||||||
|-
| Gunsmoke||||||||
|-
| Rip Van Winkel [sic]||||||||
|-
| Les Miserábles [sic]||||||||
|-
| Oklahoma!||||||||
|-
| Lawrence of Arabia||||||||
|-
| The Music Man||||||||
|-
| Annie (Play)||||||||
|-
| Annie (Movie)||||||||
|-
| Schindler's List||||||||
|-
| Mad Men||||||||
|-
| Evita||||||||
|-
| Bonnie and Clyde||||||||
|-
| Chinatown||||||||
|-
| Gandhi||||||||
|-
| The Sandlot||||||||
|-
| Back to the Future||||||||
|-
| Patton||||||||
|-
| Catch-22 (Movie)||||||||
|-
| The Great Escape||||||||
|-
| Catch-22 (Book)||||||||
|-
| M*A*S*H||film by Robert Altman||1970||19||1951
|-
| Grease||||||||
|-
| Happy Days||||||||
|-
| Platoon||||||||
|-
| The Wonder Years||||||||
|-
| Dirty Dancing||||||||
|-
| The Right Stuff||||||||
|-
| JFK||||||||
|-
| Apollo 13||film by Ron Howard||1995||25||1970
|-
| That '70s Show||TV series||1998-2006||>22|||1976-1979
|-
| The Wolf of Wall Street||film by Martin Scorsese||2013||>18||1987-1995
|-
| Freaks and Geeks||||||||
|-
| I Love the '80s||||||||
|-
| The Bridge on the River Kwai||film by David Lean||||||
|-
| American Graffiti||film by George Lucas||1973||11||1962
|-
| Apocalypse Now||film by Francis Ford Coppola||1979||10||1969
|-
| The Big Lebowski||film by the Coen Brothers||1998||7||1991
|-
| [[Wikipedia:United 93 (film)|United 93]]|| film directed by Paul Greengrass||2006||-5||2001
|-
| [[Wikipedia:I Love the '90s (U.S. TV series)|I Love the '90s]]|| TV miniseries on VH1||2004||-14||1990
|-
| [[Wikipedia:Hotel Rwanda|Hotel Rwanda]]|| film directed by Terry George||2004||-10||1994
|-
| [[Wikipedia:I Love the 2000s|I Love the 2000s]]|| TV miniseries on VH1||2014||-14||2000
|-
|
|}

* = first episode aired. † = conjectured year set in.

==Trivia==
There is a hypercorrection in ''{{w|Rip Van Winkle}}'' as ''Rip van Winkel''. Washington Irving may have misspelled ''van {{w|nl:Winkel|Winkel}}''.

It's ''{{w|Les Misérables}}'' not ''Les Miserábles''. Note that French doesn't have "á".

{{w|Lest Darkness Fall}} takes place about 1400 years in the past, but is places around the -500 years line on the graph.

==Transcript==
{{incomplete transcript}}
:'''Date of Publication'''
:[A logarithmic scale running horizontally, from 3000 BCE to past 2015 CE]
:'''Years in the Future'''
:[A logarithmic scale running vertically, from 1 billion down to 0]
:'''Stories Set in the Future''' (Science Fiction, Prediction)
::Stories set in 2015
::[A line divides this region into two. The upper side is labelled "Still Possible"; the lower side is labelled "Obsolete".]
:[from left to right...]
::Memoirs of the Twentieth Century [1733, 265 years in the future]
::Looking Backward [1888, 112 years in the future]
::Golf in the Year 2000 [1892, 108 years in the future]
::The Time Machine [1895, 800 thousand to 30 million years in the future]
::Enoch Soames [1916, ''circa'' 60 years in the future]
::1984 [1949, 35 years in the future]
::A Week in the Wales of the Future [1957, 76 years in the future]
::The Jetsons [1962-63, 100 years in the future]
::Star Trek [1966-69, 300 years in the future]
::2001: A Space Odyssey [1968, 33 years in the future]
::Space: 1999 [1975-77, 24 years in the future]
::2010: Odyssey Two [1982, 28 years in the future]
::Transformers (TV series) [1984-87, 20 years in the future]
::2061: Odyssey Three [1987, 74 years in the future]
::Star Trek: The Next Generation [1987-94, ''circa'' 500 years in the future]
::Back to the Future Part II [1989, 26 years in the future]
::Zero Wing [1989, 112 years in the future]
::Terminator 2 (1995 portion) [1991, 4 years in the future]
::3001: The Final Odyssey [1997, 1004 years in the future]
::Enterprise [2001-2005, 150 years in the future]
::This chart [2015, 0 years in the future]
:'''Years in the Past'''
:[A logarithmic scale running vertically, from 0 down past 1 billion to "Big Bang"]
:'''Stories Set in the Past''' (History, Period Fiction)
::Stories written X years ago and set 2X years ago
::[A line divides this region into two. The upper side is labelled as follows.]
::'''Former Period Pieces'''
::Stories set in the past, but created long enough ago that they were published closer to their setting than to today.
::Modern audiences may not recognize which parts were ''supposed'' to sound old.
:[from left to right...]
::The Epic of Gilgamesh [''circa'' 2100 BCE, 600 years in the past]
::The Iliad [''circa''' 800 BCE, 450 years in the past]
::History of the Peloponnesian War [''circa'' 390 BCE, 10 years in the past]
::Book of Genesis [''circa'' 500 BCE, 4000 years in the past]
::Ashokavadana [''circa'' 100 BCE, 300 years in the past]
::Gospels (various estimates) [''circa'' 250 CE, 24 to 75 years in the past]
::The Pillow Book [1000 CE, 5 years in the past]
::Water Margin [''circa'' 1300, 195 years in the past]
::Richard III [''circa'' 1590, 115 years in the past]
::Julius Caesar [1599, 1650 years in the past]
::King John [''circa'' 1600, 500 years in the past]
::Henry IV [''circa'' 1600, 190 years in the past]
::King Lear [''circa'' 1606, 3000 years in the past]
::Henry VIII [''circa'' 1612, 105 years in the past]
::The Last of the Mohicans [1826, 69 years in the past]
::Rip Van Winkel [1819, 31-51 years in the past]
::A Tale of Two Cities [1859, 60 years in the past]
::Moby-Dick [1851, around 10 years ago]
:::"Some years ago--never mind how long precisely..."
::Les Miserábles [1862, 30 years in the past]
::A Connecticut Yankee in King Arthur's Court
::Treasure Island
::Gone With the Wind
::Lest Darkness Fall
::Casablanca
::Oklahoma!
::The Ten Commandments
::The Bridge on the River Kwai
::Gunsmoke
::Catch-22 (book)
::The Flintstones
::The Great Escape
::Asterix
::Lawrence of Arabia
::The Music Man
::Bonnie and Clyde
::2001: A Space Odyssey (prologue)
::American Graffiti
::Patton
::Catch-22 (movie)
::Chinatown
::Blazing Saddles
::Apocalypse Now
::Happy Days
::Grease
::M*A*S*H
::Annie (play)
::Roots
::Chariots of Fire
::Star Wars (IV-VI)
::Annie (movie)
::The Right Stuff
::Back to the Future
::Gandhi
::Platoon
::Dirty Dancing
::Back to the Future Part III
::The Wonder Years
::JFK
::The Sandlot
::Schindler's List
::Raptor Red
::Apollo 13
::Star Wars (I-III)
::The Big Lebowski
::Evita
::Saving Private Ryan
::The Prince of Egypt
::Freaks and Geeks
::Hotel Rwanda
::I Love the '80s
::That '70s Show
::Pearl Harbor
::Ice Age
::I Love the '90s
::United 93
::300
::10,000 BC
::Year One
::The Wolf of Wall Street
::I Love the 2000s
::Mad Men
::Downton Abbey
::Star Wars (VII-IX)

{{comic discussion}}

[[Category:Large drawings]]

1491: Stories of the Past and Future

2015-02-25T18:42:22Z

141.101.80.121: /* Works listed */ Lest Darkness Fall

{{comic
| number = 1491
| date = February 25, 2015
| title = Stories of the Past and Future
| image = stories_of_the_past_and_future.png
| titletext = Little-known fact: The 'Dawn of Man' opening sequence in 2001 cuts away seconds before the Flinstones theme becomes recognizable.
}}

==Explanation==
{{incomplete|Created by a BOT - Please change this comment when editing this page.}}
''A larger version of the image is available [http://xkcd.com/1491/large/ here].''

X-axis: Date of publication.

Y-axis, "Years in the future": Number of years the story's events take place, after the story's publication.

Y-axis, "Years in the past": Number of years the story's events take place, before the story's publication.

For example, "Water Margin" was published in the 14th century (x ~= 1300) and relates events from the 12th century, about 200 years before its publication (y ~= 200 in the past).

Another example: The film ''{{w|The Bridge on the River Kwai}}'' was released in 1957 and it was set around 14 years before (~1942-43).

Grey area in the "Years in the future" part: Stories set in the future (from their publication's date), whose the story's events' date is already past (from now).

Grey area in the "Years in the past" part: Stories set in the past (from their publication's date), published closer to their setting than to today.

Taking the "years in the past" on the y-axis to be read as negatives like in most graphs one can write:

Dates on the lower line satisfy: y = x-2015. Corresponding works were published in the year x = 2015+y and are set in the year x+y = 2015+2y.

Dates on the upper line satisfy: y = 2015-x. Corresponding works were published in the year x = 2015-y and are set in the year x+y = 2015.

Thus it's clear that the definitions of the lines are consistent with each other as they follow similar but inverted functions.

In the top portion of the graph, the two sides of the line are defined as "still possible" and "obsolete" (gray area). The gray area (obsolete) expands over time, the prediction (or science fiction work) that are not confirmed by reality are doomed to be obsolete. The author mark the line of the stories set in 2015; they are the expectation for our present in different past times.

In the bottom graph, the line indicates the limit in which the publishing time is nearer to the time treated in the work than to the present. The work in the gray area could be perceived as written by contemporary writers while in most cases they refer to a further past. This is expressed in the warning: "Modern audiences may not recognize which part were supposed to sound old". This is a recurrent theme in the author's work, being already formulated in [[Period_Speech]].

The bottom of the chart has the Star Wars films, which are set "A long time ago".

===Works listed===

{| {{table}}
| align="center" style="background:#f0f0f0;"|'''Publication'''
| align="center" style="background:#f0f0f0;"|'''Description'''
| align="center" style="background:#f0f0f0;"|'''Year Written'''
| align="center" style="background:#f0f0f0;"|'''Year Difference'''
| align="center" style="background:#f0f0f0;"|'''Year Set In'''
|-
| [[Wikipedia:Memoirs of the Twentieth Century|Memoirs of the Twentieth Century]]|| book written by Samuel Madden||1733||264||1997
|-
| [[Wikipedia:Golf in the Year 2000|Golf in the Year 2000]]|| novel written by J. McCullough||1892||108||2000
|-
| [[Wikipedia:Looking Backward|Looking Backward]]|| novel written by Edward Bellamy||1888||112||2000
|-
| [[Wikipedia:Enoch Soames|Enoch Soames]]|| short story by Max Beerbohm||1897||100||1997
|-
| [[Wikipedia:The Time Machine|The Time Machine]]|| novel written by H.G. Wells||1895||800,806||802,701
|-
| [[Wikipedia:Nineteen Eighty-Four|1984]]||novel written by George Orwell||1949||35||1984
|-
| [[Wikipedia:Wythnos yng Nghymru Fydd|A Week in the Wales of the Future]]||novel written by Islwyn Ffowc Elis||1957||76||2033
|-
| [[Wikipedia:The Jetsons|The Jetsons]]||TV series produced by Hanna-Barbera||1962 *||100||2062 †
|-
| [[Wikipedia:Star Trek: The Original Series|Star Trek !TOS!]]||TV series created by Gene Roddenberry||1966 *||298||2264
|-
| [[Wikipedia:2001: A Space Odyssey (film)|2001: A Space Odyssey]]||novel written by Arthur C. Clarke||1968||33||2001
|-
| [[Wikipedia:Space: 1999|Space: 1999]]||TV series created by Gerry and Sylvia Anderson||1975 *||24||1999
|-
| [[Wikipedia:2010: Odyssey Two|2010: Odyssey Two]]||novel written by Arthur C. Clarke||1982||28||2010
|-
| [[Wikipedia:Star Trek: The Next Generation|Star Trek: The Next Generation]]||TV series created by Gene Roddenberry||1987 *||377||2364
|-
| [[Wikipedia:2061: Odyssey Three|2061: Odyssey Three]]||novel written by Arthur C. Clarke||1987||74||2061
|-
| [[Wikipedia:Zero Wing|Zero Wing]]||arcade/computer game||1989||112||2101 (previously referenced in [[887: Future Timeline]])
|-
| [[Wikipedia:3001: The Final Odyssey|3001: The Final Odyssey]]||novel written by Arthur C. Clarke||1997||1004||3001
|-
| [[Wikipedia:Star Trek: Enterprise|Enterprise]]||TV series||2001 *||150||2151
|-
| [[Wikipedia:Back to the Future Part II|Back to the Future Part II]]||film directed by Robert Zemeckis||1989||26||2015
|-
| [[Wikipedia:The Transformers (TV series)|Transformers (TV Series)]]||TV series||1984 *||~ 20||< 2010
|-
| [[Wikipedia:Terminator 2: Judgment Day|Terminator 2 (1995 Portion)]]||film directed by James Cameron||1991||4||1995
|-
| [[Wikipedia:Casablanca (film)|Casablanca]]||film directed by Michael Curtiz||1942||< 1||1941
|-
| [[Wikipedia:The Pillow Book|The Pillow Book]]||book written by Sei Shōnagon||1002||6||996
|-
| [[Wikipedia:History of the Peloponnesian War|History of the Peloponnesian War]]||history written by Thucydides||~400 BCE||~10||431-411 BCE
|-
| Moby Dick||||||||
|-
| Gospels||||||||
|-
| The Epic of Gilgamesh||||||||
|-
| The Iliad||||||||
|-
| Ashokavadana||||||||
|-
| Book of Genesis||||||||
|-
| Water Margin||||||||
|-
| King John||||||||
|-
| Henry IV||||||||
|-
| Richard III||||||||
|-
| Henry VIII||||||||
|-
| Julius Caesar||||||||
|-
| King Lear||||||||
|-
| A Conneticut Yankee in King Arthur's Court||||||||
|-
| [[wikipedia:Lest Darkness Fall|Lest Darkness Fall]]||alternate history SF novel||1939||1404||535
|-
| Asterix||French comic by Goscinny and Uderzo||1959*||2009||50 B.C.
|-
| The Ten Commandments||film by Cecil B. DeMille||1956||3412||[[wikipedia:The Exodus#Date|1446 BCE]]
|-
| The Flintstones||TV series produced by Hanna-Barbera||1960*||>2,5 million||Stone Age
|-
| 2001: A Space Odyssey (prologue)||novel written by Arthur C. Clarke||1968|||>2,5 million||Stone Age ([[wikipedia:Lower Paleolithic|Lower Paleolithic]])|
|-
| Star Wars (IV - VI)||original film trilogy ||1977-1983|| ||A long time ago
|-
| Star Wars (I - III)||prequel film trilogy||1999-2005|| ||A long time ago
|-
| Raptor Red||novel by Robert Bakker||1995||>65 million||Cretaceous Period
|-
| Star Wars (VII - IX)||sequel film trilogy||2015-2021|| ||A long time ago
|-
| Ice Age||animated films by Blue Sky Studios||2002*||>12,000||[[wikipedia:Last glacial period| Paleolithic-Mesolithic]]
|-
| 10,000 BC||film by Roland Emmerich||2008||11,992||10,000 BC
|-
| 300||film by Zack Snyder||2007||2487||[[wikipedia:Battle of Thermopylae|480 BC]]
|-
| Year One||film by Harold Ramis||2009||2008||1 AD
|-
| The Prince of Egypt||animated film by DreamWorks||1998||3412||[[wikipedia:The Exodus#Date|1446 BCE]]
|-
| Downton Abbey||||||||
|-
| Pearl Harbour||film by Michael Bay||2001||60||1941
|-
| Saving Private Ryan||film by Steven Spielberg||1998||54||1944
|-
| Chariots of Fire||film by Hugh Hudson||1981||57||1924
|-
| Blazing Saddles||film by Mel Brooks||1974||100||1874
|-
| Back to the Future Part III||film by Robert Zemeckis||1990||105||1885
|-
| Roots||||||||
|-
| Treasure Island||||||||
|-
| The Last of the Mohicans||||||||
|-
| A Tale of Two Cities||||||||
|-
| Gone With The Wind||||||||
|-
| Gunsmoke||||||||
|-
| Rip Van Winkel [sic]||||||||
|-
| Les Miserábles [sic]||||||||
|-
| Oklahoma!||||||||
|-
| Lawrence of Arabia||||||||
|-
| The Music Man||||||||
|-
| Annie (Play)||||||||
|-
| Annie (Movie)||||||||
|-
| Schindler's List||||||||
|-
| Mad Men||||||||
|-
| Evita||||||||
|-
| Bonnie and Clyde||||||||
|-
| Chinatown||||||||
|-
| Gandhi||||||||
|-
| The Sandlot||||||||
|-
| Back to the Future||||||||
|-
| Patton||||||||
|-
| Catch-22 (Movie)||||||||
|-
| The Great Escape||||||||
|-
| Catch-22 (Book)||||||||
|-
| M*A*S*H||film by Robert Altman||1970||19||1951
|-
| Grease||||||||
|-
| Happy Days||||||||
|-
| Platoon||||||||
|-
| The Wonder Years||||||||
|-
| Dirty Dancing||||||||
|-
| The Right Stuff||||||||
|-
| JFK||||||||
|-
| Apollo 13||film by Ron Howard||1995||25||1970
|-
| That '70s Show||TV series||1998-2006||>22|||1976-1979
|-
| The Wolf of Wall Street||film by Martin Scorsese||2013||>18||1987-1995
|-
| Freaks and Geeks||||||||
|-
| I Love the '80s||||||||
|-
| The Bridge on the River Kwai||film by David Lean||||||
|-
| American Graffiti||film by George Lucas||1973||11||1962
|-
| Apocalypse Now||film by Francis Ford Coppola||1979||10||1969
|-
| The Big Lebowski||film by the Coen Brothers||1998||7||1991
|-
| [[Wikipedia:United 93 (film)|United 93]]|| film directed by Paul Greengrass||2006||-5||2001
|-
| [[Wikipedia:I Love the '90s (U.S. TV series)|I Love the '90s]]|| TV miniseries on VH1||2004||-14||1990
|-
| [[Wikipedia:Hotel Rwanda|Hotel Rwanda]]|| film directed by Terry George||2004||-10||1994
|-
| [[Wikipedia:I Love the 2000s|I Love the 2000s]]|| TV miniseries on VH1||2014||-14||2000
|-
|
|}

* = first episode aired. † = conjectured year set in.

==Trivia==
There is a hypercorrection in ''{{w|Rip Van Winkle}}'' as ''Rip van Winkel''. Washington Irving may have misspelled ''van {{w|nl:Winkel|Winkel}}''.

It's ''{{w|Les Misérables}}'' not ''Les Miserábles''. Note that French doesn't have "á".

==Transcript==
{{incomplete transcript}}
:'''Date of Publication'''
:[A logarithmic scale running horizontally, from 3000 BCE to past 2015 CE]
:'''Years in the Future'''
:[A logarithmic scale running vertically, from 1 billion down to 0]
:'''Stories Set in the Future''' (Science Fiction, Prediction)
::Stories set in 2015
::[A line divides this region into two. The upper side is labelled "Still Possible"; the lower side is labelled "Obsolete".]
:[from left to right...]
::Memoirs of the Twentieth Century [1733, 265 years in the future]
::Looking Backward [1888, 112 years in the future]
::Golf in the Year 2000 [1892, 108 years in the future]
::The Time Machine [1895, 800 thousand to 30 million years in the future]
::Enoch Soames [1916, ''circa'' 60 years in the future]
::1984 [1949, 35 years in the future]
::A Week in the Wales of the Future [1957, 76 years in the future]
::The Jetsons [1962-63, 100 years in the future]
::Star Trek [1966-69, 300 years in the future]
::2001: A Space Odyssey [1968, 33 years in the future]
::Space: 1999 [1975-77, 24 years in the future]
::2010: Odyssey Two [1982, 28 years in the future]
::Transformers (TV series) [1984-87, 20 years in the future]
::2061: Odyssey Three [1987, 74 years in the future]
::Star Trek: The Next Generation [1987-94, ''circa'' 500 years in the future]
::Back to the Future Part II [1989, 26 years in the future]
::Zero Wing [1989, 112 years in the future]
::Terminator 2 (1995 portion) [1991, 4 years in the future]
::3001: The Final Odyssey [1997, 1004 years in the future]
::Enterprise [2001-2005, 150 years in the future]
::This chart [2015, 0 years in the future]
:'''Years in the Past'''
:[A logarithmic scale running vertically, from 0 down past 1 billion to "Big Bang"]
:'''Stories Set in the Past''' (History, Period Fiction)
::Stories written X years ago and set 2X years ago
::[A line divides this region into two. The upper side is labelled as follows.]
::'''Former Period Pieces'''
::Stories set in the past, but created long enough ago that they were published closer to their setting than to today.
::Modern audiences may not recognize which parts were ''supposed'' to sound old.
:[from left to right...]
::The Epic of Gilgamesh [''circa'' 2100 BCE, 600 years in the past]
::The Iliad [''circa''' 800 BCE, 450 years in the past]
::History of the Peloponnesian War [''circa'' 390 BCE, 10 years in the past]
::Book of Genesis [''circa'' 500 BCE, 4000 years in the past]
::Ashokavadana [''circa'' 100 BCE, 300 years in the past]
::Gospels (various estimates) [''circa'' 250 CE, 24 to 75 years in the past]
::The Pillow Book [1000 CE, 5 years in the past]
::Water Margin [''circa'' 1300, 195 years in the past]
::Richard III [''circa'' 1590, 115 years in the past]
::Julius Caesar [1599, 1650 years in the past]
::King John [''circa'' 1600, 500 years in the past]
::Henry IV [''circa'' 1600, 190 years in the past]
::King Lear [''circa'' 1606, 3000 years in the past]
::Henry VIII [''circa'' 1612, 105 years in the past]
::The Last of the Mohicans [1826, 69 years in the past]
::Rip Van Winkel [1819, 31-51 years in the past]
::A Tale of Two Cities [1859, 60 years in the past]
::Moby-Dick [1851, around 10 years ago]
:::"Some years ago--never mind how long precisely..."
::Les Miserábles [1862, 30 years in the past]
::A Connecticut Yankee in King Arthur's Court
::Treasure Island
::Gone With the Wind
::Lest Darkness Fall
::Casablanca
::Oklahoma!
::The Ten Commandments
::The Bridge on the River Kwai
::Gunsmoke
::Catch-22 (book)
::The Flintstones
::The Great Escape
::Asterix
::Lawrence of Arabia
::The Music Man
::Bonnie and Clyde
::2001: A Space Odyssey (prologue)
::American Graffiti
::Patton
::Catch-22 (movie)
::Chinatown
::Blazing Saddles
::Apocalypse Now
::Happy Days
::Grease
::M*A*S*H
::Annie (play)
::Roots
::Chariots of Fire
::Star Wars (IV-VI)
::Annie (movie)
::The Right Stuff
::Back to the Future
::Gandhi
::Platoon
::Dirty Dancing
::Back to the Future Part III
::The Wonder Years
::JFK
::The Sandlot
::Schindler's List
::Raptor Red
::Apollo 13
::Star Wars (I-III)
::The Big Lebowski
::Evita
::Saving Private Ryan
::The Prince of Egypt
::Freaks and Geeks
::Hotel Rwanda
::I Love the '80s
::That '70s Show
::Pearl Harbor
::Ice Age
::I Love the '90s
::United 93
::300
::10,000 BC
::Year One
::The Wolf of Wall Street
::I Love the 2000s
::Mad Men
::Downton Abbey
::Star Wars (VII-IX)

{{comic discussion}}

[[Category:Large drawings]]

Talk:1491: Stories of the Past and Future

2015-02-25T06:35:11Z

141.101.80.121: factual error?

http://xkcd.com/1491/large/ will take you to the large version, which the comic currently doesn't have a link to. I expect that will be fixed shortly. [[Special:Contributions/108.162.210.177|108.162.210.177]] 05:30, 25 February 2015 (UTC)
:I just realized he has a text link for it in the top banner. I'd delete my comment, but that's rude on a wiki. Whatever. [[Special:Contributions/108.162.210.177|108.162.210.177]] 05:35, 25 February 2015 (UTC)

The bottom diagonal seems to be mislabelled? Shouldn't it be "Stories written X years and set X years ago" instead of "set 2X years ago"?
--[[Special:Contributions/108.162.250.175|108.162.250.175]] 05:38, 25 February 2015 (UTC)

I'm not sure where to open bug tickets, but Lest Darkness Fall actually takes place ~1500 years ago, not ~500. [[Special:Contributions/141.101.80.121|141.101.80.121]] 06:35, 25 February 2015 (UTC)

Talk:1472: Geography

2015-01-12T06:57:34Z

141.101.80.121: DF

Anybody notice that he drew an isthmus but didn't label it? [[Special:Contributions/108.162.221.94|108.162.221.94]] 05:49, 12 January 2015 (UTC)

Does Randall play Dwarf Fortress? Because the perfect map to build your fort on looks about like this. Volcano near the sea is especially neat luxury. --[[Special:Contributions/141.101.80.121|141.101.80.121]] 06:57, 12 January 2015 (UTC)