By coincedence, three Indian squaws are giving birth on the same night. One has a deer hide for a bed, and gives birth to a 5 lb. boy. Another has an antellope hide and gives birth to a 6 lb. boy. The third squaw has a hippopotamus hide (she travels alot) and births an 11 lb. boy.
Which proves that the son of the squaw on the hippopotamus = the sum of the sons on the other 2 hides.