I think this is a slightly dated toy from internet guru zefrank (there's an updated version on his site which I'm less crazy about), but what a time waster! Simply drag the shapes into your canvas, and watch how they look in a kaleidoscope. It's a lot more fun than it sounds (to me, at least).

Anyway, since I've got the word kaleidoscope up here, I decided to look up the origins on wikipedia, and this is what I came up with:

"Known to the ancient Greeks, it was reinvented by the Scot Sir David Brewster in 1816 while conducting experiments on light polarization, and it was patented in 1817... Initially intended as a science tool, it was quickly copied as a toy. Brewster believed he would make money from his popular invention. However, a fault in his patent allowed others to copy his invention."

So, what I'm most curious about is what sort of "science tool" the kaleidoscope could possibly be. I could see using it as a fly swatter or a back scratcher, but a science tool? Any ideas?  Link to kaleidoscope toy.