Does the bucket look gray?
Yes, the bucket is gray.
    src        edge_attr  dst
0     0               on    1
1     2   to the left of    4
2     2               on    3
3     2  to the right of    8
4     2   to the left of    7
5     4   to the left of    7
6     4  to the right of    2
7     5    surrounded by    8
8     7  to the right of    4
9     7  to the right of    2
10    8      surrounding    5
11    8   to the left of    2