In the fourth Naked Photo podcast this photo is discussed, and there is a nice intro to it on Pete Turner's work. I hope he continues his podcasts longer than the other Pete Turner podcast I liked - George Eastman house stopped at about 15 a few years ago and I felt that the Pete Turner podcast they did was one of theirt best. Below are the links.

http://thenakedphotopodcast.com/2010/11/29/episode-4-pete-turner-rolling-ball/

http://itunes.apple.com/podcast/george-eastman-house/id260394520