1 for (int c0 = 1; c0 <= 3; c0 += 1)
2   for (int c1 = 1; c1 <= 9; c1 += 1)
3     s1(c1, c0);
4 for (int c0 = 4; c0 <= 9; c0 += 1)
5   for (int c1 = 1; c1 <= 9; c1 += 1) {
6     if (c0 % 4 == 0)
7       s0(c1, c0 / 4);
8     s1(c1, c0);
9   }
10 for (int c0 = 3; c0 <= 9; c0 += 1)
11   for (int c1 = 1; c1 <= 9; c1 += 1)
12     s0(c1, c0);
13