How tall is the green grass?
The grass is short.
    src        edge_attr  dst
0     0  to the right of    9
1     0  to the right of    2
2     2   to the left of    0
3     4               in    1
4     5  to the right of   12
5     6  to the right of   12
6     7  to the right of   12
7     8               on    3
8     8   to the left of   11
9     9   to the left of    0
10   10               on   12
11   11  to the right of    8
12   11               of   12
13   12   to the left of    5
14   12               in    1
15   12   to the left of    6
16   12   to the left of    7