What vehicles are behind the sheep?
The vehicles are cars.
    src        edge_attr  dst
0     0        on top of    9
1     0         crossing    9
2     0  to the right of    6
3     0      in front of    2
4     1  to the right of    3
5     2        on top of    9
6     2   to the left of    4
7     2           behind    0
8     2  to the right of    8
9     3        on top of    1
10    3   to the left of    1
11    4  to the right of    2
12    4  to the right of    8
13    6   to the left of    0
14    6   to the left of    9
15    8   to the left of    4
16    8        on top of    9
17    8   to the left of    2
18    9  to the right of    6