Isaac Newton and Gottfried Leibniz had a long-standing rivalry over which of them had actually discovered calculus. This led to a great deal of personal acrimony. Eventually it threatened to boil over into outright violence, when Leibniz decided he wasn’t going to take it anymore. So he got out his dueling pistols, crossed the channel, and started looking for Newton.
Newton, meanwhile, had word that Leibniz was coming, so he laid his plans.
When Leibniz arrived, he shouted, “At last, Newton, I’ve found you!”
Upon which, Newton calmly drew a square in the middle of his room, a meter on each side, and sat down in the middle of it. “On the contrary,” he said, “You’ve found Pascal.”