THE INSCRIPTION above the entrance to Plato's Academy in Athens warned, "Let none ignorant of geometry enter here."
The sign over Frank Morgan's office door in the Department of Mathematics and Statistics at Williams College, a small intellectual powerhouse nestled in the Berkshire foothills of Western Massachusetts, similarly warns (in Greek, no less). But the sign hangs over the door inside his office.
Translation: Don't expect to leave Professor Morgan's math world without learning something about geometry. Fortunately, when we meet on an oven-hot August afternoon, Professor Morgan makes it easy.