13 16
0 -1 -1 0
1 0 -1 0
2 1 -1 0
3 -0.5 -0.5 1
4 0 -0.5 1
5 0.5 -0.5 1
6 -1 0 0
7 -0.5 0 1
8 0 0 0
9 1 0 0
10 -0.5 0.5 1
11 -1 1 0
12 0 1 0
0 1 3
1 4 3
1 5 4
1 2 5
0 3 6
3 7 6
3 8 7
3 4 8
4 5 8
5 9 8
2 9 5
6 10 11
6 7 10
7 8 10
8 12 10
10 12 11