Hi All,

As I'm finalizing the CSS conversion of the Math design, I need your help on the images for the 404/Captcha/error pages. You can see the ones I used on the other StackExhange sites.

The idea is to keep it related to the site's topic, but also a bit light-hearted. For example, for Gaming site: Captcha alt text

404alt text

For Cooking site:

404 alt text

Error alt text

You can append /error, /404, /captcha to see the images from the other newly graduated Stack Exchange sites.

So, what should I use for the Math site? I think it'd be clever to use some in-joke type of math comic strips, assuming they're ok for us to use copy-right wise.

  • 6
    $\begingroup$ I think using the "does not exist" symbol ($\not\exists$) for the 404 page would either be really neat or really lame, but I can't tell which. (It would certainly be very hard to make a pretty image out of, which is why I'm not posting this as a serious suggestion.) $\endgroup$ – Rahul Oct 25 '10 at 3:59
  • $\begingroup$ @Rahul, it doesn't have to be "pretty." The goal is for the users of the site to "get it." An inside joke if you will. I think your suggestion is great. $\endgroup$ – Jin Oct 25 '10 at 4:01
  • $\begingroup$ For errors, probably the usual suspects e.g. "you divided by zero!"? For the CAPTCHA, display a calculus problem first and then "just kidding, here's the actual CAPTCHA..." $\endgroup$ – J. M. is a poor mathematician Oct 25 '10 at 6:06
  • $\begingroup$ @J.M. that's pretty clever! can you find a complex calculus formula? maybe i'll put it on blackboard graphic. I think it'd be fitting, since I'm removing the blackboard treatment from the badges. $\endgroup$ – Jin Oct 25 '10 at 6:20
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    $\begingroup$ I have quite the number of beasts in my stable, and I'll have to look over them to see what's appropriate @Jin. In the meantime, I believe the others have their own monsters they might like to see! (I was thinking of this replacing the "hello fellow robot" image one sees in the CAPTCHA). $\endgroup$ – J. M. is a poor mathematician Oct 25 '10 at 6:35
  • $\begingroup$ Now I think about something like Venn diagrams. The set of MSE pages and showing that you are out of it. Some kind of figure is better than a symbol, more interesting to view. BTW look at cstheory.stackexchange.com/404 $\endgroup$ – Yrogirg Jun 8 '12 at 11:01

Following Jin's encouragement, I'm posting my comment as an answer so people can vote on it.

For the 404 page: The "does not exist" symbol. $$\LARGE\unicode{x2204}$$

  • $\begingroup$ Wouldn't $\neg\exists$ be better? $\endgroup$ – user23211 Jun 8 '12 at 16:53

How about the slogan: "404 is not a very interesting number"

referring to the Ramanujan-Hardy taxi story.


Maybe this XKCD comic for the captcha?

XKCD #329

Or maybe it's not math-related enough.


Mathematical fallacy for 500 (/error)? For example,

\begin{align} a &= b \\\\ a^2 &= ab \\\\ a^2 - b^2 &= ab - b^2 \\\\ (a+b)(a-b) &= b(a-b) \\\\ a+b &= b \\\\ a+a &= a \quad (∵ a=b) \\\\ 2a &= a \\\\ 2 &= 1\quad?! \end{align}



There might be a rival for $\nexists$, namely the empty set:


Now I wonder if ⊥ was considered for 404 at theoretical computer science.

  • $\begingroup$ I really hope not. $\endgroup$ – JeffE Jun 10 '12 at 15:59


In the text field below, give a proof that for integers $n \ge 3$, there do not exist integers $x,y,z$ with $x^n + y^n = z^n$.

  • $\begingroup$ Fermat's Last Theorem? shouldn't it be n>=2 ? $\endgroup$ – Aarthi Jun 8 '12 at 19:01
  • $\begingroup$ @Aarthi Recall the $(3,4,5)$ triangle and other Pythagorean triples. One should also exclude trivial solutions such as $(0,0,0)$ and $(1,0,1)$. $\endgroup$ – Dylan Moreland Jun 8 '12 at 19:16
  • $\begingroup$ Ah ha. I stand corrected, which is totally understandable. :D $\endgroup$ – Aarthi Jun 8 '12 at 19:18
  • $\begingroup$ HaHA, that would be the best CAPTCHA ever.. $\endgroup$ – user249332 Feb 2 '16 at 21:28

May be something about "Divide by zero" for the error page?

Recursive "Divide by zero" macro

Waterfall "Divide by zero" macro


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