digraph {
       rankdir = LR;
       node [color = green];
       1;  2;  3;
       5;  6;  7;
       9; 10; 11;

       node [color = orange];
       4;
       8;
       12;

       node [color = blue, fillcolor = yellow, style = filled];
       0;

       12 -> 11;
       12 -> 10;
       12 -> 9;
       11 -> 10;
       11 -> 9
       11 -> 8
       10 -> 9
       10 -> 8
       10 -> 7
       9 -> 8
       9 -> 7
       9 -> 6
       8 -> 7
       8 -> 6
       8 -> 5
       7 -> 6
       7 -> 5
       7 -> 4
       6 -> 5
       6 -> 4
       6 -> 3
       5 -> 4
       5 -> 3
       5 -> 2
       4 -> 3
       4 -> 2
       4 -> 1
       3 -> 2
       3 -> 1
       2 -> 1
       3 -> 0
       2 -> 0
       1 -> 0
}