What is the horse pulling?
The horse is pulling the wagon.
    src        edge_attr  dst
0     0   to the left of    8
1     0   to the left of    1
2     1  to the right of   10
3     1          pulling   16
4     1  to the right of    2
..  ...              ...  ...
58   15  to the right of    7
59   15   to the left of    9
60   16   to the left of    9
61   16  to the right of    2
62   16        pulled by    1

[63 rows x 3 columns]