Are there either any letters or buses in the picture?
Yes, there are letters.
     src        edge_attr  dst
0      0   to the left of   17
1      0  to the right of   16
2      0   to the left of   20
3      0   to the left of   19
4      0   to the left of    8
..   ...              ...  ...
151   28  to the right of    3
152   28  to the right of    0
153   28   to the left of    9
154   28  to the right of   23
155   28  to the right of   18

[156 rows x 3 columns]