What's on the post?
The clock is on the post.
   src        edge_attr  dst
0    0  to the right of    6
1    2   to the left of    6
2    6   to the left of    7
3    6   to the left of    0
4    6  to the right of    2
5    7  to the right of    8
6    7  to the right of    6
7    8   to the left of    7
8   10               on    3