It’s not who you are that holds you back, it’s who you think you’re not.

When I'm working on a problem, I never think about beauty. I think only how to solve the problem. But when I have finished, if the solution is not beautiful, I know it is wrong.

The second half of a man’s life is made up of nothing but the habits he has acquired during the first half.

Progress isn't made by early risers. It's made by lazy men trying to find easier ways to do something.