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