对于2n=4,可接受的12条步行道为:
(0, 0, -1), (0, -1, -1), (0, 0, -1), (0 ,0, 0);
(0, 0, -1), (0, 0, 0), (0, 0, -1), (0 ,0, 0);
(0, 0, -1), (0, 0, 0), (1, 0, 0), (0 ,0, 0);
(0, 0, -1), (1, 0, -1), (0, 0, -1), (0 ,0, 0);
(0, 0, -1), (1, 0, -1), (1, 0, 0), (0 ,0, 0);
(1, 0, 0), (0, -1, -1), (0, 0, -1), (0 ,0, 0);
(1, 0, 0), (0, 0, 0), (0, 0, -1), (0 ,0, 0);
(1, 0, 0), (0, 0, 0), (1, 0, 0), (0 ,0, 0);
(1, 0, 0), (1, 0, -1), (0, 0, -1), (0 ,0, 0);
(1, 0, 0), (1, 0, -1), (1, 0, 0), (0 ,0, 0);
(1, 0, 0), (1, 1, 0), (0, 0, -1), (0 ,0, 0);
(1, 0, 0), (1, 1, 0), (1, 0, 0), (0 ,0, 0).