(I enjoyed the pun) On the right is the margin that was too small to contain Fermat's alleged proof of his "last theorem". https://en.wikipedia.org/wiki/Fermat

(I enjoyed the pun) On the right is the margin that was too small to contain Fermat's alleged proof of his "last theorem". https://en.wikipedia.org/wiki/Fermat%27s_Last_Theorem https://en.wikipedia.org/wiki/Fermat%27s_Last_Theorem