Ross Atkins famously shaved half of his beard so that a picture of his face could be used as an example for teaching people about geometric transformations: the determinant is positive if the beard is on the correct side, and negative otherwise. He once told me how he was talking to someone (after last meeting six months ago), who said, "Wow, Ross, you still have half a beard! You should have switched sides; nobody would notice!" The punch-line is that Ross had indeed switched sides... Sincerely, Adam P. Goucher

----- Original Message ----- From: Dan Asimov Sent: 04/27/14 09:02 PM To: math-fun Subject: Re: [math-fun] Novel ways to present proofs

Ha! As a grad student at Berkeley, I cut off one half of my beard, just for fun, and left it that way for several months. Never thought of the pedagogical applications, though.

--Dan

P.S. Nu, so how many hairs *are* in a beard?

Veit Elser wrote:

----- beard bisection

When word came down from on high, “teach them how to estimate”, I responded by estimating the number of hairs in a beard. At the first lecture I showed up with a full beard, the second with half shaved off, etc. each time with yet another half removed. When there was just a few square mm of beard left we counted the hairs. ----- _______________________________________________ math-fun mailing list math-fun@mailman.xmission.com http://mailman.xmission.com/cgi-bin/mailman/listinfo/math-fun