I had also included that one in an earlier post: http://www.billthelizard.com/2009/07/six-visual-proofs_25.html http://www.billthelizard.com/2009/07/six-visual-

I had also included that one in an earlier post: http://www.billthelizard.com/2009/07/six-visual-proofs_25.html http://www.billthelizard.com/2009/07/six-visual-proofs_25.ht... (scroll down to the 5th "proof"). I think I like the image you used to visualize the relationship a little bit better than the one I used.