When making something， always get a few extras — extra material， extra parts， extra space， extra finishes. The extras serve as backups for mistakes， reduce stress， and fill your inventory for the future. They are the cheapest insurance.

心灵不是需要填满的容器，而是需要点燃的火炬。

我认为数学之所以有价值，是因为它具有这种令人难以置信的结构，你可以探索和发现。