Where is the fence?
The fence is in the pen.
    src        edge_attr  dst
0     1               on    6
1     1   to the left of    5
2     1  to the right of    2
3     2   to the left of    1
4     2   to the left of    4
5     3               in    0
6     4               on    6
7     4   to the left of    5
8     4  to the right of    2
9     5  to the right of    1
10    5  to the right of    4