It was the custom among women of a particular tribe of North American plains Indians that when a pregnant woman's time was due, she would take the skin of large animal, go out into the wilderness, lie down on the skin, and give birth to a new member of the tribe.

On this occasion, in the fullness of time, three women came due at the same time, so the three of them trekked out into the wilderness to have their babies.

One lay down on a buffalo skin, one lay down on a bear skin, and on lay down on a hippopotamus hide.

The one on the buffalo skin gave birth to a baby boy. The one on the bear skin gave birth to a baby girl. The one on the hippopotamus hide gave birth to twins, a boy and a girl.

This proves the Pythagorean theorem that "the squaw on the hippopotamus is equal to the squaws on the other two hides…."

Don Firth