What type of material is the fence made of?
The fence is made of wood.
    src        edge_attr  dst
0     0               on    2
1     0       hanging on    2
2     0  to the right of    3
3     1   to the left of    6
4     1   to the left of    5
5     2  to the right of    3
6     3   to the left of    6
7     3   to the left of    2
8     3   to the left of    0
9     4   to the left of    9
10    4   to the left of   13
11    4   to the left of   14
12    4   to the left of    5
13    5  to the right of    4
14    5  to the right of    1
15    6  to the right of    3
16    6  to the right of    1
17    7  to the right of   10
18    9  to the right of    4
19   10   to the left of    7
20   13  to the right of    4
21   14               on   13
22   14  to the right of    4