What do the trees and the mountains have in common?
The color, both the trees and the mountains are green.
    src        edge_attr  dst
0     0               of    4
1     1   on the side of    4
2     3   to the left of   11
3     3   to the left of    7
4     4   to the left of   10
5     4               on    2
6     4   to the left of   12
7     7  to the right of    3
8    10  to the right of    4
9    11  to the right of    3
10   12  to the right of    4