I've seen something like this in a couple of forms years ago.

BTW, you asked me before if I had a favorite number and, since I don't like anything that smacks of mathematics, I could only pull a number out of the air. I thought of one more the other day. "9" I like the fact that it is three times three and, therefore, has a nifty sort of symmetry. Unusual for an odd number. IMHO