What is the fence made of?
The fence is made of metal.
    src        edge_attr  dst
0     0   to the left of    4
1     0  to the right of    6
2     2   to the left of    5
3     2           behind    9
4     2   to the left of    3
5     2             near    3
6     3  to the right of    2
7     3  to the right of    7
8     3          next to    2
9     4  to the right of    0
10    5  to the right of    7
11    5  to the right of    2
12    6   to the left of    0
13    7   to the left of   10
14    7   to the left of    3
15    7   to the left of    5
16    7  to the right of    8
17    8   to the left of    7
18    9           beside    2
19    9      in front of    2
20   10  to the right of    7