Ridiculous episode, excellent prop.
HMS built this one as I recall. It's actually far simpler than it looks. It's basically some laser-cut acrylic circles with either vinyl or screen-printing on them and a wood base with some round slots cut, probably with a table saw set to an angle or mill with a slotting saw.
Anybody know anything more about it? I'm sure I've seen some better photos somewhere but I can't find anything in my notebooks.