You can lose your way groping among the shadows of the past. It's frightening how many people and things there are in a man's past that have stopped moving. The living people we've lost in the crypts of time sleep so soundly side by side with the dead that the same darkness envelops them all. As we grow older, we no longer know whom to awaken, the living or the dead.
Henri Poincare
I then began to study arithmetical questions without any great apparent result, and without suspecting that they could have the least connexion with my previous researches. Disgusted at my want of success, I went away to spend a few days at the seaside, and thought of entirely different things. One day, as I was walking on the cliff, the idea came to me, again with the same characteristics of conciseness, suddenness, and immediate certainty, that arithmetical transformations of indefinite ternary quadratic forms are identical with those of non-Euclidian geometry.
