IQ Test Examiner: All bears are white where there is always snow; in Novaya Zemlya there is always snow; what color are the bears there? Soviet Union Peasant: I have seen only black bears and I do not ...

Here’s a simple problem, illustrated simply, that will have you cocking your head and wondering how it’s done. You won’t be the first. Aristotle (reputedly) first took a whack at this, and Galileo ...