What vehicle is in front of the wall?
The vehicle is a van.
    src        edge_attr  dst
0     0   to the left of   12
1     1  to the right of    4
2     1  to the right of    7
3     1  to the right of    8
4     1   to the left of    5
5     1  to the right of   10
6     1  to the right of    6
7     2  to the right of    5
8     2           behind   12
9     2  to the right of   12
10    2  to the right of    9
11    3   to the left of   12
12    4  to the right of   10
13    4   to the left of    1
14    4   to the left of    5
15    5   on the side of   12
16    5   to the left of    2
17    5  to the right of    1
18    5  to the right of    6
19    5  to the right of    4
20    5  to the right of   10
21    6   to the left of    5
22    6   to the left of    1
23    6  to the right of   10
24    7   to the left of    1
25    8   to the left of    1
26    8  on the front of   12
27    9   to the left of    2
28   10   to the left of    1
29   10  to the right of   11
30   10  on the front of   12
31   10   to the left of    5
32   10   to the left of    4
33   10   to the left of    6
34   11   to the left of   10
35   11   to the left of   12
36   12  to the right of    3
37   12      in front of    2
38   12   to the left of    2
39   12  to the right of    0
40   12  to the right of   11