What is covering the boots?
The snow is covering the boots.
   src        edge_attr  dst
0    0   to the left of    9
1    3         covering    4
2    4       covered by    3
3    5  to the right of    6
4    6   to the left of    5
5    8               of    2
6    9  to the right of   10
7    9  to the right of    0
8   10   to the left of    9