n=4的一些解
..0..1....0..1....0..1....0..1....0..1....0..1....0..1....0..1....0..1....0..1
..1..2....2..3....2..3....1..0....2..3....2..0....2..3....2..0....2..0....1..2
..0..3....3..1....0..2....2..3....3..1....3..2....0..1....1..3....3..1....3..0
..3..2....0..2....3..1....3..2....2..0....1..3....3..2....3..2....2..3....2..3