For fifteen days I struggled to prove that no functions
analogous to those I have since called Fuchsian functions could
exist; I was then very ignorant. Every day I sat down at my
work table where I spent an hour or two; I tried a great number
of combinations and arrived at no result. One evening, contrary
to my custom, I took black coffee; I could not go to sleep;
ideas swarmed up in clouds; I sensed them clashing until, to put
it so, a pair would hook together to form a stable combination.
By morning I had established the existence of a class of
Fuchsian functions, those derived from the hypergeometric series.
I had only to write up the results which took me a few hours.
-- Henri Poincare, Science et Methode