数学不仅仅是关于数字、方程、计算或算法：它是关于理解的。
"The only way to deal with an unfree world is to become so absolutely free that your very existence is an act of rebellion."
It is not the strength of the body that counts, but the strength of the spirit.
One can't proceed from the informal to the formal by formal means.
Responsible forestry isn't about limiting progress—it's about redefining what progress means.