"The past is a country we can never return to, but whose borders we are always crossing."

Follow your heart, and use it to lead your life. Anything else is secondary.

每一本书都是一段旅程，而每一段旅程都会让你有所改变。

数学的美在于它是一种可以以其他任何方式都无法描述宇宙的语言。