What color does the truck on the left side have?
The truck has blue color.
    src        edge_attr  dst
0     0   to the left of    2
1     0   to the left of    3
2     1   to the left of    5
3     1   to the left of    4
4     2  to the right of    0
5     2   to the left of    5
6     2   to the left of    4
7     2  to the right of    6
8     3  to the right of    0
9     3  to the right of    6
10    3               on    2
11    4               on    5
12    4  to the right of    1
13    4  to the right of    2
14    5  to the right of    2
15    5  to the right of    1
16    6   to the left of    3
17    6   to the left of    2