On which side is the ladder?
The ladder is on the left of the image.
     src        edge_attr  dst
0      0   to the left of   21
1      0   to the left of   18
2      0               on    1
3      1   to the left of   21
4      1   to the left of   18
..   ...              ...  ...
131   21   to the left of   17
132   21               on   18
133   21  to the right of    0
134   21  to the right of    1
135   22               on   23

[136 rows x 3 columns]