A frontiersman went into an Indian village to purchase a wife. The chief showed him three young women. The first was seated on a deer skin and could be purchased for the sum of five ponies. The second was seated on a buffalo skin and could also be purchased for five ponies. The third young woman was seated on a hippopotamus skin and could be purchased for ten ponies. "Why does this one cost so much more?" asked the man. "You know," replied chief Pythagoras, "the squaw on the hippopotamus is equal to the sum of the squaws on the other two hides."