Looks like there is some interest in this Luminations puzzle these past few weeks on eBay. Here's a link that has a solution for it, and a bunch of other puzzles too.

http://home.att.net/~abcmcfarren/math/math.htm

BTW, I had someone make a good point about how rare things seem to show up in groups on eBay. He called it his theory of "Subsequent Scarcity":

Person A offers for sale an item that is scarce enough to generate interest sufficient to raise the price above what would be considered normal. Person B, who can get their hands on the same item, but who has never thought of selling it, sees the price and gets dollar signs in their eyes. They immediately offer the same item for sale, hoping to capitalize on the lingering interest left in the unfulfilled buyers from the original sale.

By the way, this is not just abstract theory - there is a practical application that can be summarized: Don't ever get in a bidding frenzy for a scarce item, in most cases another will come along soon enough (you hope).


I'd quote his name here too, but dunno if he'd want me to!

Sandy