人生中最美好的时刻，不是那些被动、接受、放松的时光……最美好的时刻通常发生在一个人自愿努力去完成一项艰难而有价值的事情时，身体或心灵被拉伸到极限的时候。

The biggest room in the world is the room for improvement.

There is nothing in the world so irresistibly contagious as laughter and good humor.

数学之美在于它能够以精确而优雅的方式描述世界。

On innovation: "I think frugality drives innovation， just like other constraints do. One of the only ways to get out of a tight box is to invent your way out."

系统越复杂，理解越少。