Do you see any fences that are not made of wood?
Yes, there is a fence that is made of metal.
    src        edge_attr  dst
0     0  to the right of    6
1     0  to the right of    5
2     1   to the left of   11
3     2   to the left of   11
4     3  to the right of    6
5     3  to the right of    5
6     3  to the right of    8
7     5   to the left of    0
8     5   to the left of    8
9     5   to the left of    3
10    6   to the left of    0
11    6   to the left of    3
12    8   to the left of    3
13    8  to the right of    5
14   10   to the left of   11
15   11  to the right of   10
16   11  to the right of    2
17   11  to the right of    1