Which kind of vehicle is red?
The vehicle is a truck.
   src        edge_attr  dst
0    1   to the left of    5
1    1   to the left of    4
2    2  to the right of    3
3    3   to the left of    2
4    4   to the left of    6
5    4  to the right of    1
6    5  to the right of    1
7    6  to the right of    4