What is in front of the tree that the building is behind of?
The signal light is in front of the tree.
    src        edge_attr  dst
0     0  to the right of    6
1     0   to the left of    8
2     1   to the left of    6
3     2   to the left of    6
4     3   to the left of    6
5     4           behind   10
6     4          next to   10
7     4      in front of    8
8     5            above   10
9     5   to the left of    6
10    5  to the right of    9
11    6  to the right of    3
12    6   to the left of    8
13    6  to the right of    5
14    6  to the right of   10
15    6   to the left of    0
16    6  to the right of    2
17    6  to the right of    1
18    8           behind    4
19    8  to the right of    0
20    8  to the right of    6
21    9   to the left of    5
22   10   on the side of    6
23   10             near    4
24   10      in front of    4
25   10            below    5
26   10   to the left of    6