What's the number on?
The number is on the motorbike.
    src        edge_attr  dst
0     0               on    6
1     0   on the back of    6
2     0   to the left of    7
3     1  to the right of   10
4     1               of    6
5     1  to the right of    3
6     2   to the left of    9
7     3   to the left of    9
8     3               of    6
9     3   to the left of    1
10    7  to the right of    0
11    9               on    6
12    9  to the right of    2
13    9  to the right of    3
14   10   to the left of    1