[math-fun] Slightly harder 15 puzzle

If you happen to have a 15 puzzle lying around with a removable piece, you can make a harder puzzle by bandaging the pieces as follows: + - - - - + | A A E b | | F c E E | | F D g   | |   D h i | + - - - - + Puzzle: Move AA from the upper-left corner to lower-right. If a move is counted as moving 1 piece any direction (including L-shaped paths)any number of squares, 131 moves are minimum. Second puzzle: Is this the hardest 4x4 Sliding Block Puzzle there is? --Neil Bickford