You're given a 3x3 board of a tile puzzle, with 8 tiles numbered 1 to 8, and an empty spot. You can move any tile adjacent to the empty spot, to the empty spot, creating an empty spot where the tile originally was. The goal is to find a series of moves that will solve the board, i.e. get [ [1, 2, 3], [4, 5, 6], [7, 8, - ] ] where - is the empty tile.