What do the fence and the post have in common?
The color, both the fence and the post are black.
    src        edge_attr  dst
0     0               on    3
1     2            below    4
2     3  to the right of    8
3     4            above    6
4     4            below    8
5     4           behind    6
6     4             near    6
7     4      in front of    8
8     4               on    2
9     6             near    4
10    6      in front of    4
11    7               on    4
12    8   to the left of    3
13    8            above    4
14    8           behind    4