What is the ground made of?
The ground is made of concrete.
    src        edge_attr  dst
0     0   to the left of   22
1     0               on    2
2     1  to the right of   24
3     1   to the left of   13
4     2   to the left of   15
..  ...              ...  ...
58   24  to the right of   12
59   24           behind    3
60   24   to the left of   12
61   24   to the left of    3
62   24   to the left of    9

[63 rows x 3 columns]