Does the clear glass look clean?
Yes, the glass is clean.
   src        edge_attr  dst
0    1  to the right of    6
1    2  to the right of    6
2    4  to the right of    6
3    5  to the right of    6
4    6   to the left of    2
5    6   to the left of    1
6    6   to the left of    5
7    6   to the left of    4
8    6   to the left of    7
9    7  to the right of    6