A city is not a collection of machines but a container of life.
In programming, as in everything else, to be in error is to be reborn.
In mathematics, the journey of discovery is often more rewarding than the destination itself.
语言是一种自由创造的过程；其法则和原则是固定的，但生成原则的使用方式是自由且无限多样的。
Mathematics is not about numbers, equations, computations, or algorithms: it is about understanding.
数学不是关于数字、方程、计算或算法的：它是关于理解的。
学习数学的唯一方法就是做数学。