On Mon, 18 Aug 2008 05:58:03 -0500, nick hull wrote:



The one part I lack is a floating ball, larger than 3² and smaller than
5².

One possibility:

http://www.gazingballoutlet.com/Stai...eel-Balls/30-1

Styrofoam balls are readily avaliable, but I think they'd need to be
coated with something for use as a floating plug.