This http://img238.imageshack.us/img238/8445/arscombinatoria8qp.png (excuse me while I learn HTML) is a mock-up of a file I've started on the ars combinatoria.

Does any one happen to know the name for the method used in the illustration? I think I may have heard a related term before, though more in reference to... ah... those curves produced in trigonometry using a fan of sloping straight lines.