He usually appears in public with a lost umbrella in each hand. He prefers to face the blackboard and turn his back on the class. He writes A; he says B; he means C; but it should be D.

He usually appears in public with a lost umbrella in each hand. He prefers to face the blackboard and turn his back on the class. He writes A; he says B; he means C; but it should be D.

How to Solve It: A New Aspect of Mathematical Method – G. Polya

I am hoping to buy this book soon.  Apparently Microsoft used to give copies of it to all of its junior developers.