Two things about Mie Gakure: 1) It appears to be fourth dimensional Crystal Castles. 2) I need it now. It was mentioned in XKCD and I'm not the only person freaking out about it; article with video demo here. I don't know whether it will help in discussions of free will but, more importantly, it will be cool.
I wonder if this was the first product placement in XKCD?