Is the traffic light different in color than the tree?
No, both the traffic light and the tree are green.
    src        edge_attr  dst
0     0   to the left of   14
1     0   to the left of    8
2     0   to the left of    3
3     0   to the left of    1
4     0   to the left of    6
5     0   to the left of    4
6     1  to the right of    7
7     1  to the right of    3
8     1  to the right of    8
9     1   to the left of   16
10    1  to the right of    2
11    1  to the right of    0
12    2   to the left of   16
13    2   to the left of    1
14    3   to the left of    1
15    3  to the right of    0
16    4               on    1
17    4  to the right of    0
18    5   to the left of    7
19    5   to the left of   14
20    6  to the right of    0
21    6               on   14
22    7   to the left of    1
23    7  to the right of    5
24    7  to the right of   12
25    8   to the left of    1
26    8  to the right of    0
27    9  to the right of   16
28    9  to the right of   14
29   10   to the left of   14
30   12   to the left of    7
31   12   to the left of   14
32   13  to the right of   16
33   13  to the right of   14
34   14   to the left of    9
35   14  to the right of   12
36   14  to the right of   10
37   14   to the left of   13
38   14  to the right of    5
39   14  to the right of    0
40   16   to the left of    9
41   16  to the right of    2
42   16  to the right of    1
43   16   to the left of   13