There's a great book called "Flatland", by Edwin Abbott, which i'm betting Joe has read. It's about a square who lives in flatland, who is visited by a sphere. as the sphere passes through Flatland, all the square can perceive is a circle getting bigger, then smaller again (he can tell it's a circle by feeling how smooth it is, and a few other techniques).
it's only about 100 pages, and definatly worth a read.
I beleive somebody wrote a kind of sequel as well, but i can't remember what it is called...
found a link to an online version of the book:
Flatland: A romance of Many Dimesions [ December 01, 2004: Message edited by: fred rosenberger ]