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