I just found this article on the solvability of these puzzles: https://www.cs.bham.ac.uk/~mdr/teaching/modules04/java2/TilesSolvability.html https://www.cs.bham

I just found this article on the solvability of these puzzles: https://www.cs.bham.ac.uk/~mdr/teaching/modules04/java2/TilesSolvability.html https://www.cs.bham.ac.uk/~mdr/teaching/modules04/java2/Tile...