Where are the trees?
The trees are on the hill top.
    src        edge_attr  dst
0     0  to the right of    3
1     0  to the right of   10
2     0  to the right of    4
3     2               on    9
4     3   to the left of   12
5     3   to the left of    7
6     3   to the left of    0
7     3   to the left of   11
8     4   to the left of    0
9     4   to the left of   12
10    4   to the left of   11
11    6  to the right of   10
12    7  to the right of    3
13    7  to the right of   10
14   10   to the left of   11
15   10   to the left of   13
16   10   to the left of    6
17   10   to the left of    0
18   10   to the left of   12
19   10   to the left of    7
20   11  to the right of   10
21   11  to the right of    3
22   11  to the right of    4
23   12  to the right of   10
24   12  to the right of    3
25   12  to the right of    4
26   13  to the right of   10