Here's another cool thing George Hart wrote about in a paper that I recently incorporated into a book I'm editing for the MAA. Look at this photo of a rubber band on George's fingers: https://www.flickr.com/photos/thane/18741252973/in/dateposted-public/ Now pick up a rubber band yourself with one hand, and see if you can figure out how get that rubber band into that same "Pentadigitation" configuration onto your own fingers without using your other hand to help you. Just figuring out to get it onto one hand's fingers with *two hands* is already tricky. But George explains how to do it with one hand. Cool. BTW, if "cool" is a dated word, perhaps "fun," as in "math-fun", is also? Maybe my participation in a "fun" forum suggests my possible membership in a no longer fashionable generation, perhaps one even composed of "idiots"? It would be good to know. On Thu, Jul 2, 2015 at 1:10 PM, Hilarie Orman <ho@alum.mit.edu> wrote:
A cool thing is that a square rotating on a catenary is is the inverse of a parabola rotating on a line.
The interesting questions are "why is a hanging chain the roulette of a parabola?" "why does a hanging chain have a succinct expression?" and "what does gravity have to do with it?"
Hilarie
Date: Wed, 1 Jul 2015 22:59:09 -0400 From: James Propp <jamespropp@gmail.com> Subject: Re: [math-fun] Draft of "The Lessons of a Square-Wheeled Trike"
I included the draft as an attachment in my earlier email, forgetting that "we" (math-fun) don't "do" attachments.
I've posted the draft at http://mathenchant.org/8-museum.rtf ; comments are welcome.
Jim Propp
On Tue, Jun 30, 2015 at 3:35 PM, James Propp <jamespropp@gmail.com> wrote:
I've finished a draft of installment #1 (as opposed to #0) of "Mathematical Enchantments", and I'd welcome comments.
Jim Propp
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