What is the material of the fence?
The fence is made of wood.
    src        edge_attr  dst
0     0   to the left of    5
1     0   to the left of   14
2     0   to the left of    9
3     2  to the right of    7
4     5  to the right of   17
5     5   to the left of   14
6     5  to the right of    0
7     5   to the left of    9
8     5   to the left of   10
9     6  to the right of    7
10    6  walking through   15
11    7   to the left of    6
12    7   to the left of    2
13    8   to the left of   10
14    8   to the left of    9
15    8         lying in   15
16    8   to the left of   14
17    9  to the right of   16
18    9   to the left of   10
19    9  to the right of    0
20    9  to the right of    8
21    9  to the right of    5
22   10  to the right of    8
23   10  to the right of   17
24   10  to the right of   14
25   10  to the right of    5
26   10  to the right of    9
27   10  to the right of   16
28   10  to the right of   12
29   12  to the right of   17
30   12   to the left of   10
31   14   to the left of   10
32   14  to the right of   16
33   14  to the right of    5
34   14  to the right of    0
35   14  to the right of   17
36   14  to the right of    8
37   16   to the left of   14
38   16   to the left of   10
39   16   to the left of    9
40   17   to the left of   14
41   17   to the left of    5
42   17   to the left of   12
43   17   to the left of   10