What material is the black fence?
The fence is made of metal.
    src        edge_attr  dst
0     0  to the right of    2
1     0  to the right of   20
2     1               on    0
3     2   to the left of    3
4     2   to the left of    0
..  ...              ...  ...
73   27   to the left of    4
74   27  to the right of    5
75   28   to the left of    7
76   28  to the right of   11
77   28               of    8

[78 rows x 3 columns]