To make them comfortable, he put one on a bearskin, one on a buffalo skin, and one on a hippapotamus skin.
The one on the bearskin had a son. The one on the buffalo skin had a son. But the one on the hippo skin had twin sons.
The moral? The squaw of the hippomatomus is equal to the sons of the squaws of the two other hides...
 
The Celtic knotwork on this page was found here
and is freely available