Following is a demo of the maze_left_wall program.
?- solve(X). X = [[2, 1], [2, 2], [3, 2], [3, 3], [4, 3], [5, 3], [5, 2], [5, 3], [5, 4], [5, 5], [5, 4], [5, 3], [4, 3], [3, 3], [3, 4], [3, 5], [2, 5], [2, 6]]