Which side is the knife on?
The knife is on the right of the image.
   src        edge_attr  dst
0    0  to the right of    2
1    0  to the right of    1
2    0               on    7
3    1   to the left of    0
4    2   to the left of    0
5    2               on    7
6    4               on    7
7    5               on    7
8    7               on    1