Found via Roger Darlington’s blog, this thing is seriously freaking me out.
Update: Thanks to Mandie, the non-mathematically inclined can understand how the flash mind reader works. I knew it had to be something simple like that (not being particularly “mystical”), but I couldn’t figure it out.
Here is the mathmatical proof, if you were wondering about the magic behind it.
I was fairly entranced with it the first time I encountered the 'game' and your post motivated me to go on a quest. 🙂 It was something that I've been curious about for awhile, but too lazy to look up.