What is on the post?
The sign is on the post.
    src        edge_attr  dst
0     0   to the left of    5
1     0   to the left of    7
2     0   to the left of    8
3     1  to the right of   15
4     1   to the left of   13
5     5  to the right of    7
6     5   to the left of    6
7     5  to the right of    0
8     5   to the left of    8
9     6  to the right of    5
10    6  to the right of    8
11    7  to the right of    0
12    7   to the left of    5
13    8  to the right of    5
14    8   to the left of    6
15    8  to the right of    0
16    9               on    4
17   11  to the right of   12
18   12   to the left of   11
19   13  to the right of    1
20   13  to the right of   15
21   14               on   11
22   15   to the left of   13
23   15   to the left of    1
24   16               on    7