"To live is the rarest thing in the world. Most people exist, that is all."

The strength of a habit is a function of the number of times it has been reinforced.

最勇敢的行为仍然是为自己思考，而且是大声说出来。

最有力的时刻是无言的时刻。

数学不仅仅是一种工具；它是一种思维方式。