What is on the post?
The sign is on the post.
    src        edge_attr  dst
0     0  to the right of    9
1     0  to the right of    7
2     0   to the left of   16
3     1   to the left of    2
4     2   to the left of   14
5     2  to the right of    1
6     3      in front of   18
7     4   to the left of    5
8     4   to the left of   10
9     4   to the left of   14
10    4           behind   16
11    5  to the right of   16
12    5  to the right of    4
13    6               on    0
14    6   to the left of   16
15    6  to the right of    7
16    7   to the left of    0
17    7   to the left of   17
18    7   to the left of   16
19    7   to the left of    6
20    9   to the left of    0
21    9   to the left of   16
22   10  to the right of    4
23   11            below   16
24   12   to the left of   17
25   12   to the left of   16
26   14  to the right of    2
27   14  to the right of    4
28   16  to the right of    0
29   16  to the right of    9
30   16  to the right of   17
31   16  to the right of   12
32   16            above   11
33   16  to the right of    7
34   16      in front of    4
35   16   to the left of    5
36   16  to the right of    6
37   17   to the left of   16
38   17  to the right of   12
39   17  to the right of    7
40   18           behind    3