What is the stop sign in front of?
The stop sign is in front of the field.
    src        edge_attr  dst
0     0        on top of    1
1     2               on    3
2     3   to the left of   12
3     3      in front of    9
4     3  to the right of   13
5     3  to the right of    9
6     3  to the right of    5
7     5   to the left of    3
8     6  to the right of   10
9     7               of    6
10    9   to the left of    3
11   10   to the left of    6
12   10      standing in    9
13   10     walking near    9
14   11  to the right of   13
15   12  to the right of    3
16   13   to the left of    3
17   13   to the left of   11