Do you see clean windows in the picture?
Yes, there is a clean window.
    src        edge_attr  dst
0     1        on top of    7
1     1  to the right of    2
2     1  to the right of   13
3     1               on    7
4     1  to the right of   17
..  ...              ...  ...
94   20   to the left of    9
95   20   to the left of    8
96   20   to the left of    1
97   20   to the left of   11
98   20  to the right of   12

[99 rows x 3 columns]