"The joy of drawing is in the doing, not in the finished product."

Thoughts are the shadows of our feelings always darker， emptier， simpler.

数学不知道种族或地理界限；对于数学来说，文化世界是一个国家。

人类的未来掌握在那些能够将智慧和美的火炬带入黑暗中的人手中。

If you're not stubborn, you'll give up on experiments too soon. And if you're not flexible, you'll pound your head against the wall and you won't see a different solution to a problem you're trying to solve.