针对4 X 4的一些解决方案:
..0....0....0....0....1....1....0....1....1....1....1....0....0....0....1....1
..1....1....3....3....0....0....3....3....0....0....2....1....3....1....0....2
..1....0....3....2....3....0....3....0....0....1....0....1....0....0....3....0
..0....3....1....0....2....2....2....2....1....0....2....3....1....2....0....1