Interfaces keep things tidy, but don't accelerate growth: Functions do.
In mathematics, you don't understand things. You just get used to them.
来吧,一旦你觉得自己懂得了什么,就必须换一种角度来看。这可能显得很荒唐或者愚蠢,但必须试一下。
The elements of mind are to be discovered by systematic introspection.