What material makes up the fence that is to the left of the tennis racket?
The fence is made of metal.
    src        edge_attr  dst
0     0  to the right of   17
1     1  to the right of   16
2     1  to the right of   12
3     2   to the left of   19
4     2  to the right of   16
5     2  to the right of   12
6     3   to the left of   11
7     3  to the right of   17
8     3  to the right of    5
9     4       sitting on    1
10    4       sitting in    1
11    5   to the left of   10
12    5   to the left of   11
13    5   to the left of    3
14    6  to the right of   16
15    7  to the right of    9
16    7  to the right of    8
17    8   to the left of    7
18    9   to the left of    7
19    9  to the right of   12
20   10  to the right of    5
21   10  to the right of   17
22   11  to the right of    3
23   11  to the right of    5
24   11  to the right of   17
25   12   to the left of   19
26   12   to the left of    2
27   12   to the left of    1
28   12   to the left of    9
29   16   to the left of    1
30   16   to the left of    6
31   16   to the left of    2
32   17   to the left of    3
33   17   to the left of   10
34   17   to the left of   11
35   17   to the left of    0
36   19  to the right of   12
37   19  to the right of    2
38   20          wearing   15