> -Z0
0 0
2 2
4 0
> -Z3
0 0
2 2
0 4
> -Z6
0 4
1 3
2 4
> -Z9
1 3
2 4
3 3
2 2
> -Z12
3 3
2 2
3 1
> -Z15
3 1
3 3
4 2
4 0
> -Z18
2 4
4 2
4 4