Aristotle, Pascal and Newton are playing hide-and-seek. Aristotle is ‘it’, and faces towards a tree, counting to one hundred. Pascal looks around, then hides behind a bush. Newton walks into a space, marks out a metre square, and stands in it. Aristotle gets to 100, and turns around. “I see Newton!”, he cries. “No,” says Newton, “One Newton per square metre is a Pascal.”