Simple implementation of the Knight's Tour problem.
It uses a cool heuristic. Take a look at line 73. With that present, it finds a result very quickly, generating a graph like the one at http://imgur.com/a/Ycrng#pEIWc
Without that line, it struggles mightily to search the exponentially-large space, and produces something more like this graph: http://imgur.com/a/Ycrng#VEJHS
Cool, huh?