Are there trucks to the right of the boat?
Yes, there is a truck to the right of the boat.
    src        edge_attr  dst
0     1   to the left of   13
1     2  to the right of   12
2     4  to the right of    6
3     5   to the left of   10
4     6   to the left of    4
5     6   to the left of   13
6    10  to the right of    5
7    12   to the left of    2
8    13  to the right of    1
9    13  to the right of    6
10   13  to the right of   15
11   15   to the left of   13
12   15       growing in   11