What is on the black post?
The lamp is on the post.
    src        edge_attr  dst
0     0   to the left of   15
1     3               on   12
2     3   to the left of    5
3     5  to the right of   12
4     5  to the right of   11
5     5  to the right of    3
6     8  to the right of    9
7     9   to the left of    8
8     9   to the left of   11
9    11   to the left of   15
10   11   to the left of    5
11   11  to the right of   14
12   11  to the right of    9
13   12   to the left of    5
14   14   to the left of   11
15   15  to the right of    0
16   15  to the right of   11