Aug 7, 2013 8:05 AM
So you've just reduced quantum mechanics to a single equation and solved the mystery of the Hound of the Baskervilles - now you need something to unwind with. But that Rubik's cube is too easy! Matching colors, how kindergarten is that? What you need is the Sudoku Cube Puzzle ($6) - try to get numbers one through nine on each side.