explain xkcd - User contributions [en]

3228: Day Counter

2026-04-03T21:28:13Z

DiamondNether90: /* Explanation */

{{comic
| number = 3228
| date = April 3, 2026
| title = Day Counter
| image = day_counter_2x.png
| imagesize = 319x287px
| noexpand = true
| titletext = It has been −2,147,483,648 days since our last integer overflow.
}}

==Explanation==

{{incomplete|This page was created -.000000000000000032 days ago. Don't remove this notice too soon.}}

A common feature of an industrial setting is a prominent sign announcing how many days have elapsed since the last workplace accident. The sign is typically updated each day to a number one higher — or back to zero, if there ''has'' been an accident. Such signs are intended to foster a culture of safety among the workers in the facility, since presumably no one wants to suffer the embarrassment of being the one to have caused an accident that resets the number to 0.

In this comic, a similar sign highlights the number of days since the last floating-point error. Floating-point errors occur because most computers can devote only a finite amount of storage for each {{w|Floating-point arithmetic|floating point number}} or other fraction. However, many {{w|real numbers}} and {{w|rational numbers}} theoretically require an infinite number of digits to represent them. For example, the ordinary fraction ⅓ is represented in decimal as 0.3333333333…, where the 3's repeat forever. When a number is truncated to fit in the finite amount of space, precision is inevitably lost, resulting in a slight roundoff error. Unless carefully controlled, these roundoff errors can accumulate, significantly degrading the accuracy of floating-point computations. For example, although ⅓ + ⅓ + ⅓ should obviously equal 1, a finite-precision calculation like 0.333 + 0.333 + 0.333 might show a misleading result of 0.999. The amount of required space for rational numbers is not universal, it depends on the base used (⅓ in base 3 requires just two digits: 0.1). Floating point arithmetic standards, like the popular IEEE 754, define how and when an approximation should take place, leading to predictable results, but they don't respect some basic properties of common arithmetic operations, which someone may take for granted, e.g. in floating point arithmetic addition and multiplication are commutative (a+b=b+a; a*b=b*a), but aren't guarantied to be associative ((a+b)+c≈a+(b+c)); (a*b)*c≈a*(b*c)).

This issue is exacerbated on computers which use binary arithmetic (i.e., virtually all computers today), since in binary, the ordinary fraction 1/10 is represented as the infinitely-repeating base-2 fraction <tt>0.000110011001100110011</tt>…. A classic example is that, depending on circumstances, the calculation 0.1 + 0.2 might [https://stackoverflow.com/questions/588004/is-floating-point-math-broken seem to give an answer of 0.30000001].

Evidently, in the programming facility shown in the comic, a floating-point error has occurred today, and an attempt has been made to update the sign to say "It has been 0 days since...". But the number 0 is displayed incorrectly, as the very small negative number −0.00000000000000044. Perhaps the error that was made today was the very error that occurred in updating the sign! (This would of course violate {{w|causality}}, but in comedy, self-referential humor beats causality every time.)

As an example of how the number −0.00000000000000044 could have arisen when 0 was intended, consider this simple {{w|C (programming language)|C}} program:

#include <stdio.h>
int main()
{
double d = 19;
for(int i = 0; i < 10; i++) d -= 1.9;
printf("%.17f\n", d);
}

The program starts with the number 19, and subtracts 1.9 from it, ten times. Mathematically, we would expect the result to be 0. However, the number 1.9 cannot be represented exactly in binary, nor can the intermediate results 17.1, 15.2, 13.3, etc. The cascading roundoff errors conspire to produce a result of −0.00000000000000044 instead of the expected 0.

In the comic, such an error creates the ridiculous illusion that −0.00000000000000044 days have passed, which implies a 'negative' number of days, which is impossible{{cn}}. It also, even if it was a positive number, would mean that much less than a nanosecond had passed since the last error, which would be an unfeasably short amount of time. Of course, the joke is that in making the sign showing the amount of time since a floating point error was last made, they are creating a floating point error, meaning the sign is invalid. Also, if they tried to reset the sign, they might make the same error again, repeating the cycle over & over, which would not be ideal.

Coincidentally enough, [[Cueball]] is also floating — off his seat in this case. The seat itself looks the same as the chair in [[2144]], possibly meaning making people levitate is one of its numerous settings.

Floating point errors are particularly common in programming, especially in languages that implicitly convert decimal numbers to binary floating point, so an approximation is already made at conversion leading to unexpected results. The title text cites another common programming problem, integer overflow. When a value gets bigger than the biggest integer that can be represented in a certain format, it typically "wraps around" to the smallest value. In case of 32-bit signed integers it may wrap from 231−1 (2,147,483,647) to −231 (−2,147,483,648). 2,147,483,647 days from the comic's date of publication (April 3rd, 2026) is approximately October 12th of the year 5,881,636, assuming no changes in the lengths of the day and year, or in other aspects of time measurement.

Strangely enough, when the comic was first published the sign number was −0.00000000000000017 days. It was changed later though, for unknown reasons.

Integer overflow was the topic of [[571: Can't Sleep]].

==Transcript==
[White Hat, Ponytail, Cueball, and Megan are all below a large sign. White Hat and Ponytail appear to be discussing something, while Cueball is sitting at his desk working on a laptop and Megan is walking away. The sign has text on it, as well as a large display presumably meant to show a number.]

:[Sign:] It has been
:[Display:] -0.00000000000000044
:[Sign:] days since our last floating point error

{{comic discussion}}<noinclude>[[Category:Interactive comics]][[Category:Dynamic comics]]
[[Category:Programming]]
[[Category:Math]]
[[Category:Comics featuring White Hat]]
[[Category:Comics featuring Ponytail]]
[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Megan]]

Talk:1562: I in Team

2026-03-26T22:30:53Z

DiamondNether90:

There is no I in team, but there is an M and an E.[[Special:Contributions/162.158.56.215|162.158.56.215]] 08:26, 10 August 2015 (UTC)
: Ha, yes -- but they are backwards [[User:Spongebog|Spongebog]] ([[User talk:Spongebog|talk]]) 15:37, 10 August 2015 (UTC)

Check it out! there's "l" in "vowels"! --[[Special:Contributions/141.101.89.222|141.101.89.222]] 08:51, 10 August 2015 (UTC)

<sarcasm>There is an (annagram of) Randal in "People who don't understand how a proverb works" </sarcasm> No, seriously this is just cueball being a smart-ass. --[[Special:Contributions/162.158.91.230|162.158.91.230]] 08:53, 10 August 2015 (UTC)

There's no I in team, but there is an I in pie; there's an I in meat pie and meat is an anagram of team, so... {{unsigned ip|141.101.99.82}}

:There's a 999999 in pi. {{unsigned ip|198.41.239.32}}

: BTW, it's called the Feynman Point. It's got a pretty interesting backstory. {{unsigned ip|162.158.72.191}}

:: Doesn't pi contain every possible number sequence though? [[Special:Contributions/162.158.91.235|162.158.91.235]] 11:17, 10 August 2015 (UTC)

::: No. There is no evidence that pi includes an offset of pi.
:::There is no I in team, but there is meat... blessed meat :::Simpson drool:: {{unsigned|Cwallenpoole}}

:::: ''finite'' sequence. the kate bush conjecture is unproven. {{unsigned ip|141.101.98.34}}

::::: Though pic is an irrational number, meaning that you could theoretically find your birthday, your SSN, even a binary representation of your DNA sequence somewhere in pi's sequence. [[User:ChromoTec|ChromoTec]] ([[User talk:ChromoTec|talk]]) 15:30, 5 August 2017 (UTC)ChromoTec

:::::: That is ''not'' what irrational number means. Just because it cannot be expressed as a decimal does not mean that every possible decimal sequence necessarily occurs. [[Special:Contributions/162.158.63.118|162.158.63.118]] 13:50, 22 October 2018 (UTC)

:::::: To make it clear: Pi is an endless string of digits after the decimal point, and there is no repeating element at the end, and it cannot be represented by a fraction. It is easy to (falsely) conclude that, to follow this rules, there is each and every (finite) sequence in it somewhere. However it is (with enough processing time) possible to determine any finite amount of digits of pi. So let's say we analyse the first 10^10^10^10 digits of pi, and you look for your finite sequence, let's say your social security number. Either it is in it (that is no proof that EVERY number-sequence is in there), or it is not. In case it is not, there is no proof (yet?), that there is not a certain "rule" after the (10^10^10^10)+1 digit, that e.g. the digit 5 is not appearing anymore. If your social security number contains a 5, it wouldn't be in pi if it's not within the first 10^10^10^10 digits, while pi's digits could still be non repeating and endless. Therefore it actually cannot be concluded that pi contains every finite sequence of numbers. --[[User:Lupo|Lupo]] ([[User talk:Lupo|talk]]) 09:24, 2 October 2019 (UTC)

:::::: The numbers that contain all possible finite combinations of digits are called normal numbers. Square root of two, pi, ln(2), and e are all believed to be normal numbers, but there's no easy way to prove it.[[Special:Contributions/172.69.247.50|172.69.247.50]] 13:28, 28 June 2023 (UTC)

:::::: The number 0.1101010001010001010001000001... (1 if digit is in a prime position, 0 otherwise) is irrational, but clearly doesn't contain every finite substring of numbers (consider '2'). [[User:DiamondNether90|DiamondNether90]] ([[User talk:DiamondNether90|talk]]) 22:30, 26 March 2026 (UTC)

The arbitrariness of this saying was demonstrated considerably more elegantly in Jeffrey Rowland's Wigu: "There is no I in 'team', but there is in 'family'." [[Special:Contributions/198.41.242.93|198.41.242.93]] 11:56, 10 August 2015 (UTC)

This joke is not self-referential, it's metalingual. See https://en.wikipedia.org/wiki/Jakobson%27s_functions_of_language [[User:Xhfz|Xhfz]] ([[User talk:Xhfz|talk]]) 13:10, 10 August 2015 (UTC)

[http://rlv.zcache.com/i_in_team_there_it_is_hidden_in_the_a_hole_tshirt-r0aff1796c915419aaa4c3f9c73794dcf_f0yq2_1024.jpg There is]. --[[Special:Contributions/141.101.98.185|141.101.98.185]] 16:18, 10 August 2015 (UTC)

: That's deep. --[[Special:Contributions/108.162.229.188|108.162.229.188]] 18:05, 10 August 2015 (UTC)

It is interesting that Randall worded Cueball's dialogue as "There is a 'U' in People who apparently don't understand...". There is just that one 'U', in "understand". If he'd said instead something like "There is a 'U' in People who apparently don't get...", the reference to Hairy through 'U'/you would've been entirely allusional!
- Vik [[Special:Contributions/108.162.225.76|108.162.225.76]] 19:30, 10 August 2015 (UTC)

This comment is my way of noting and speculating that it makes sense that the origin of "No I in Team" is from baseball pitchers: They're the only team sport player I know of who is regularly replaced mid-game for reasons besides injury. If a pitcher thinks he's on a hot streak, but the coach replaces him because reasons, a phrase like like "No I in Team" may be needed to smooth over the resulting disagreement, regardless of whether the coach or the pitcher has their respective heads up their asses or not. [[Special:Contributions/199.27.133.53|199.27.133.53]] 20:05, 10 August 2015 (UTC)

But there IS an I in team! http://i.imgur.com/prPC7BX.jpg [[Special:Contributions/141.101.85.151|141.101.85.151]] 02:16, 11 August 2015 (UTC)

I think it's interesting that there is exactly one "u" in "People who apparently don't understand the relationship between orthography and meaning", which has 76 letters. "U" isn't a terribly infrequent letter. [[Special:Contributions/108.162.221.133|108.162.221.133]] 04:42, 11 August 2015 (UTC)
: The frequency of "u" is about 2.8%. Assuming a binomial distribution, one "u" out of 76 letters is about a 25% probability. Nothing of significance here, even though 2 "u"s would be slightly more likely. --[[Special:Contributions/198.41.235.101|198.41.235.101]] 14:43, 11 August 2015 (UTC)
:: You make it sound like the text was generated randomly. Randall obviously chose the sentence carefully to contain a single U. Here's a far more extreme example, an entire 50,000 word novel written without the letter E: https://en.wikipedia.org/wiki/Gadsby_(novel). Should we calculate the odds of this happening?!

I think part of the joke that is missed in the current explanation is that cueball is responding with a less vulgar version of the common retort: "But there is a 'U' in c*nt."[[Special:Contributions/108.162.250.188|108.162.250.188]] 09:32, 11 August 2015 (UTC)

:I have to say I've never heard that retort before. I'll have to try and remember to throw it into conversation next time I get the chance! --[[User:Pudder|Pudder]] ([[User talk:Pudder|talk]]) 14:02, 11 August 2015 (UTC)

"There is no I in team" is also sometimes used on voice coms for video games or other situations where the listener may not be able to identify the individual by voice, to explain why they should identify themselves in third person. --[[Special:Contributions/199.27.133.83|199.27.133.83]] 02:37, 31 August 2015 (UTC)

Is this comic related to {{w|metalinguistics}}? [[Special:Contributions/172.69.134.71|172.69.134.71]] 00:05, 3 July 2023 (UTC)

[http://conwaylife.com/w/index.php?title=User:ColorfulGalaxy/Encyclopedia_of_numbers&diff=156361&oldid=156358 There is no "#" in "blue".] [[User:ChristmasGospel|ChristmasGospel]] ([[User talk:ChristmasGospel|talk]]) 17:27, 16 November 2024 (UTC)

571: Can't Sleep

2026-03-21T08:57:44Z

DiamondNether90: Tried (and probably failed) to explain signed integer overflow

{{comic
| number = 571
| date = April 20, 2009
| title = Can't Sleep
| image = cant sleep.png
| titletext = If androids someday DO dream of electric sheep, don't forget to declare sheepCount as a long int.
}}

==Explanation==
[[Cueball]] is in bed and is having trouble sleeping. He tries the old standby of {{w|counting sheep}} as they jump over a fence, but upon reaching 32,767 sheep, 65535 sheep jump back over the fence and start counting up again from -32,768. This is a reference to an integer overflow, when an increasing amount (sheep in this case) suddenly overflows and shows up as a negative value. This is because when a whole number or integer is represented in a digital form, such as on a computer, the number's range is limited by the amount of space used to store it. When the greatest possible number given the storage space is exceeded, an arithmetic overflow occurs, which may result (depending on the used language among other things) in starting over at the least possible number given the storage space, similar to a car's odometer. Imagine an odometer with six digits reaching 999999. Upon driving one more mile or km, the digits will roll back over to 000000. The negative number comes from half of the possible values representing positive numbers, and half representing negative numbers. For the odometer, imagine numbers over 500000 represented negative numbers, so 500000 represented -500000, 500001 represented -499999, etc. Causing or failing to prevent integer overflow is a common mistake by programmers that may have software security consequences. Some languages like C/C++ even leaves the signed integer overflow ''undefined behavior'', it may or may not wrap to the beginning, the instruction can be ignored or may cause the software to crash.

In this case, the least and greatest possible numbers are -32,768 and 32,767, which implies that Cueball's brain would only be 16-bit. In addition, it's clear that the number is designated as a signed number, meaning that it can be either positive or negative.

However, even if Cueball had this limitation, it would never actually pose a problem. By 32,767 sheep, at a rate of one sheep per second, Cueball has been counting for 9.101 hours (or about 9 hours 6 minutes). This would signify that he has extreme insomnia and probably needs treatment, and also that he has spent the entire night counting, and therefore would just get up and start the day rather than count sheep all over again from -32,768.

The title text refers to the 1968 Philip K. Dick science fiction novel ''{{w|Do Androids Dream of Electric Sheep?}}'', which was adapted into the perhaps more widely known Ridley Scott directed 1982 film ''Blade Runner''. The implication is that if we ever do create androids that dream of electric sheep, we should make sure to give them sufficient storage space to store numbers large enough such that an arithmetic overflow will be far less likely to occur, even if they count for a long time. A "long int" depends on machine architecture, but it typically consists of four bytes rather than two, so instead of being limited to a range from -32,768 to 32,767 the number will be capable of storing numbers from -2,147,483,648 to 2,147,483,647, which would take 68.1 years to exhaust (at the rate of 1 sheep/sec). "sheepCount" is a possible name for a variable to be used in a computer program. Declaring a variable tells the computer that it should allocate a portion of memory to be associated with the variable name given. No spaces are used because variables cannot contain spaces, for a reason that would take a little too long to properly explain here.

==Transcript==
:[Cueball is in bed, presumably trying to sleep. The top of each panel is a thought bubble showing sheep leaping over a fence and Cueball's counting and the sheeps baaing is written above the sheeps. Two sheep are jumping from left to right in the first panel.]
:1... 2...
:Sheep: Baaa

:[Two sheep are jumping from left to right. Cueball is holding his pillow.]
:... 1,306... 1,307...
:Sheep: Baaa

:[A whole flock of sheep (nine visible) is jumping over the fence from right to left; the first and last sheep is cut off at the edge of the frame. Cueball is now sitting up looking up at his thought bubble.]
:... 32,767 ...-32,768...
:Sheep: Baaa baaa baaaa baaa ba
:Cueball: ?

:[Two sheep are again jumping from left to right. Cueball is holding his pillow over his head.]
:...-32,767... -32,766...
:Sheep: Baaa

{{comic discussion}}

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