Some solutions for n=4
.....0........0........0........0........0........0........0........0
....1.2......1.0......1.1......1.0......0.1......1.0......1.0......1.2
...2.2.2....0.1.0....2.1.3....1.0.2....2.2.3....2.0.0....0.0.2....1.2.2
..2.1.2.3..2.2.0.0..3.3.1.4..1.2.1.1..2.3.3.4..0.0.2.2..3.2.0.2..0.1.2.0
|