Do you see envelopes or buses?
No, there are no buses or envelopes.
     src        edge_attr  dst
0      0   to the left of   37
1      0  to the right of   40
2      0  to the right of   42
3      0  to the right of    6
4      0  to the right of   10
..   ...              ...  ...
672   49  to the right of   23
673   49  to the right of   24
674   49  to the right of    6
675   49   to the left of   37
676   49  to the right of   27

[677 rows x 3 columns]