The field is covered by what?
The field is covered by the grass.
     src        edge_attr  dst
0      0   to the left of   17
1      0   to the left of    9
2      0  to the right of   21
3      1   to the left of    9
4      1   to the left of    4
..   ...              ...  ...
107   26   to the left of   28
108   27         covering    2
109   28  to the right of   26
110   28   to the left of   17
111   28   to the left of    9

[112 rows x 3 columns]