What is in front of the trees?
The train is in front of the trees.
    src        edge_attr  dst
0     0           behind    6
1     0   to the left of    6
2     0   to the left of    9
3     3   to the left of    6
4     3   to the left of    9
5     6  to the right of    0
6     6   to the left of    8
7     6      in front of    0
8     6  to the right of    7
9     6  to the right of    3
10    7   to the left of    9
11    7   to the left of    6
12    8  to the right of    6
13    9  to the right of    7
14    9  to the right of    0
15    9  to the right of    3