Which color are the tall trees?
The trees are green.
   src        edge_attr  dst
0    3  to the right of    4
1    4   to the left of    9
2    4   to the left of    3
3    4   to the left of    8
4    4   to the left of    5
5    5  to the right of    4
6    8  to the right of    4
7    9  to the right of    4