What's the skateboard on?
The skateboard is on the bike.
    src        edge_attr  dst
0     1  to the right of   12
1     2   to the left of   13
2     2   to the left of   11
3     2   to the left of   10
4     2               on   10
5     5      in front of    9
6     8               in    7
7    10  to the right of    2
8    10  to the right of   12
9    11  to the right of   12
10   11  to the right of    2
11   11   to the left of   13
12   12   to the left of   11
13   12   to the left of   10
14   12   to the left of    1
15   13  to the right of    2
16   13  to the right of   11