The essence of mathematics lies in its freedom.
设定目标是将不可见变为可见的第一步。
The great secret that all old people share is that you really haven't changed in seventy or eighty years. Your body changes, but you don't change at all.
所有老年人共有的一个大秘密是，你在七八十年里其实并没有改变。你的身体变了，但你一点也没变。这当然会引起很大的困惑。
I write to understand what I think.
The world is so full of simple, obvious, and beautiful things that it's a wonder anyone ever bothers to invent anything at all.