Forests teach us patience—growth takes time, but the rewards are everlasting.
Happiness is secured through virtue; it is a good attained by man's own will.
Reflect upon your present blessings, of which every man has plenty; not on your past misfortunes, of which all men have some.
自动控制的根本问题是在存在干扰的情况下维持期望状态。
The beauty of mathematics only shows itself to more patient followers.