My geometry teacher was sometimes acute, and sometimes obtuse, but always, he was right. A biologist, a statistician, a mathematician and a computer scientist are on a photo-safari in africa. They drive out on the savannah in their jeep, stop and scout the horizon with their binoculars. We only know there's one white zebra. Pie are round.
Cornbread are square.
Algebraists do it in groups. Von Neumann and Nobert Weiner were both the subject of many dotty professor stories. One time one of his students tried to get more helpful information by asking if there was another way to solve the problem. Weiner was in fact very absent minded. Since she was certain that he would forget that they had moved and where they had moved to, she wrote down the new address on a piece of paper, and gave it to him.