What is in front of the tree?
The rocks are in front of the tree.
    src        edge_attr  dst
0     0               of    5
1     0   to the left of    3
2     0  to the right of   11
3     1  to the right of   11
4     1               of    5
5     1   to the left of    3
6     1  to the right of    7
7     2   to the left of    5
8     2   to the left of    7
9     3  to the right of    0
10    3  to the right of    7
11    3  to the right of    5
12    3  to the right of    1
13    5  to the right of    2
14    5   to the left of    3
15    5  to the right of   11
16    5      in front of   11
17    6               of    5
18    6  to the right of    7
19    7               of    5
20    7   to the left of    9
21    7   to the left of    8
22    7   to the left of    3
23    7  to the right of    2
24    7   to the left of    6
25    7   to the left of    1
26    8               of    5
27    8  to the right of    7
28    9               of    5
29    9  to the right of    7
30   10           behind   11
31   10   to the left of   12
32   10  to the right of   11
33   11      in front of   10
34   11   to the left of    5
35   11   to the left of    1
36   11   to the left of    0
37   11   to the left of   10
38   11           behind    5
39   12  to the right of   10