Combinatorics is like the art of counting without actually counting.
把灯笼背在背上的人,有黑影遮住前路。
A mind needs books like as word needs a whetstone.
天的核心是“生生不息”,默默造就万物却没有穷尽;地的核心是“公平有序”,均匀滋养万物却不会混乱。
人生而自由,却无处不在地受着枷锁。