“I have discovered a truly remarkable woman which this binder is too small to contain”

Seen amongst the customer reviews on this Amazon.com product :

In case you don’t get it, it’s related to Fermat’s Last Theorem. Pierre de Fermat was reading a book that talked about Pythagoras’ theorem and how the equation x^{2}+y^{2}=z^{2} had infinitely many solutions for x,y,z>0. Then he wrote in the margin of the book he was reading that the equation x^{n}+y^{n}=z^{n} had no solutions for n>2, said “I have found a remarkable proof of this, but this margin is too small to contain it”

This scribbled note was only found many years later, after Fermat had died. He never wrote down his remarkable proof, and modern opinion is that he didn’t actually have one.