c width = 6, time = 0.077675
s td 13 7 20
b 1 4 7 8 16 17 18 19
b 2 1 4 8 16 17 18 19
b 3 1 8 12 16 17
b 4 1 4 8 13 18
b 5 3 4 5 7 17 18 19
b 6 4 5 9 18 19
b 7 5 7 17 18 19 20
b 8 4 6 7 16
b 9 4 7 8 15 17 18 19
b 10 11 15 17 18
b 11 12 1 14
b 12 17 12 10
b 13 5 2
2 3
2 4
1 2
5 6
5 7
1 5
1 8
9 10
1 9
3 11
3 12
5 13