Which kind of vehicle is in the field?
The vehicle is a tractor.
    src        edge_attr  dst
0     0  to the right of    4
1     2  to the right of    9
2     4   to the left of    0
3     5           behind   13
4     9   to the left of   10
5     9   to the left of    2
6    10  to the right of   13
7    10  to the right of    9
8    11               in    3
9    13               in    3
10   13      in front of    5
11   13   to the left of   10