可持续性不是终点，而是日常实践。

在一个国家中，一个公民的自由就是所有人的自由。

The first question I ask myself when something doesn't seem to be beautiful is why do I think it's not beautiful. And very shortly you discover that there is no reason.

数学证明的优雅类似于精心设计的算法的美丽。