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