What is surrounding the train?
The trees are surrounding the train.
    src        edge_attr  dst
0     1     reflected on   10
1     2  to the right of   19
2     2  to the right of    5
3     3  to the right of    5
4     3  to the right of    6
5     4  to the right of    5
6     4  to the right of    6
7     4  to the right of   19
8     5   to the left of    2
9     5   to the left of    3
10    5  to the right of    9
11    5   to the left of    7
12    5   to the left of    6
13    5   to the left of    4
14    5  to the right of   19
15    6  to the right of    9
16    6  to the right of   19
17    6  to the right of    5
18    6   to the left of    3
19    6   to the left of    4
20    6   to the left of    7
21    7          next to   10
22    7             near   10
23    7  to the right of    5
24    7  to the right of    6
25    7    surrounded by   13
26    9   to the left of    5
27    9   to the left of    6
28   10             near    7
29   10             near   13
30   13  to the right of   19
31   13      surrounding    7
32   13          next to   10
33   16  to the right of   20
34   19   to the left of    2
35   19   to the left of    4
36   19   to the left of    5
37   19   to the left of    6
38   19   to the left of   13
39   20   to the left of   16
40   21               of   22
41   22        on top of   21
42   22       growing in   10
43   22           inside   10