What kind of animal is the boy sitting on?
The boy is sitting on the horse.
    src        edge_attr  dst
0     1  to the right of   15
1     3   to the left of   11
2     3  to the right of   15
3     3  to the right of    4
4     3  to the right of    5
5     4   to the left of    3
6     5   to the left of    3
7     8   to the left of   13
8    11  to the right of    3
9    11  to the right of   14
10   12       sitting on   15
11   12          wearing   16
12   12  to the right of   13
13   13   to the left of   16
14   13   to the left of   12
15   13  to the right of    8
16   14   to the left of   11
17   15   to the left of    3
18   15               in   10
19   15   to the left of    1
20   16  to the right of   13