"Life is like riding a bicycle. To keep your balance, you must keep moving."

Albert Einstein, 1930

"Einstein was a giant. His head was in the clouds, but his feet were on the ground. But those of us who are not that tall have to choose!"

Richard P. Feynman

"For a successful technology, reality must take precedence over public relations, for Nature cannot be fooled."

Richard P. Feynman, 1986

"If you don't know where you're going, you'll end up somewhere else."

Yogi Berra

"A ship in harbor is safe, but that is not what ships are built for."

John A. Shedd, 1928

"In theory there is no difference between theory and practice. In practice there is."

Benjamin Brewster, 1882

"If you find yourself in a hole, stop digging."

First law of holes, adage attributed to Washington Post, 1911.

"The first principle is that you must not fool yourself - and you are the easiest person to fool."

Richard Feynman, 1974.

"Peace cannot be kept by force. It can only be achieved through understanding."

Albert Einstein, 1930.