Show HN: I made a deceptively simple but hard sliding puzzle
If this puzzle reminds you of a Rubik's cube that is not a coincidence.  The mathematical structure of both puzzles is essentially the same. The moves in both puzzles form a non-abelian group, which is the source of the challenge. See <a href="http://web.mit.edu/sp.268/www/rubik.pdf" rel="nofollow">http://web.mit.edu/sp.268/www/rubik.pdf</a><p>In fact, a fun meta-puzzle is to find a three-dimensional analog to this two-dimensional puzzle.