Every visitor to the oasis town of Dunhuang in northwestern China encounters a puzzling image of three hares (or three rabbits) that appear to be chasing each other in a never-ending circle. This motif is prominently displayed at the entrance to the Dunhuang Museum and is a popular decoration on the scarves, paintings, carpets, and t-shirts sold in the local tourist markets.

While each individual hare has two ears, the three hares together have a total of only three ears instead of six. Of course, the answer to this riddle lies in the fact that the three ears are arranged to form a triangle, with each pair of adjacent hares sharing an ear.