And when his audience grew bored, he would spring into the air and do a back flip with a half twist.

The deepest problems in mathematics often arise from the simplest questions.

我是个糟糕的撒谎者，所以我写歌。

We are just an advanced breed of monkeys on a minor planet of a very average star. But we can understand the Universe. That makes us something very special.

The great advantage of old age is that you can be as rude as you like.