From Mark's Intro page
Originally uploaded in Pedagogy in Action:Library:Teaching with Simulations.

Image 17197 is a 120 by 120 pixel WebP
Uploaded: Oct9 09

Last Modified: 2009-10-09 22:36:46
Permanent URL:

The file is referred to in 2 pages
From Fair's homepage
If you wish to use this item outside this site in ways that exceed fair use (see you must seek permission from its creator.