Do the truck and the fence have a different colors?
No, both the truck and the fence are blue.
    src        edge_attr  dst
0     0  to the right of   12
1     0  to the right of    6
2     0  to the right of   18
3     1               on    7
4     1  to the right of   20
5     1  to the right of   15
6     1  to the right of   10
7     3   to the left of   13
8     4  to the right of   13
9     4   to the left of   12
10    5  to the right of   13
11    5   to the left of   12
12    6   to the left of   12
13    6               on    7
14    6               on    0
15    6   to the left of   18
16    6   to the left of    0
17    7  to the right of    9
18    9   to the left of    7
19    9   to the left of   15
20   10      in front of   20
21   10   to the left of    1
22   10  to the right of   20
23   11               on    8
24   12  to the right of    6
25   12  to the right of   13
26   12  to the right of    4
27   12  to the right of    5
28   12   to the left of    0
29   13  to the right of    3
30   13   to the left of    5
31   13   to the left of    4
32   13   to the left of   12
33   15  to the right of    9
34   15   to the left of    1
35   18   to the left of    0
36   18  to the right of    6
37   20         crossing   19
38   20   to the left of    1
39   20   to the left of   10
40   20           behind   10
41   20               in   15