When he was a cadet at West Point, California humorist George Derby had attended a class on military strategy.

“A thousand men are besieging a fortress that contains these quantities of equipment and provisions,” said the instructor, pointing to a chart. “It is a military axiom that at the end of 45 days the fort will surrender. If you were in command of this fortress, what would you do?”

Derby raised his hand and said, “I would march out, let the enemy in, and at the end of 45 days I would change places with him.”