How clean do you think is the toilet that the tissue paper is on?
The toilet is clean.
    src        edge_attr  dst
0     0   to the left of    3
1     1   to the left of    3
2     1   to the left of    5
3     2               on    1
4     2   to the left of    3
5     3  to the right of    1
6     3  to the right of    0
7     3  to the right of    4
8     3  to the right of    2
9     4               on    0
10    4   to the left of    3
11    5  to the right of    1
12    6               on    3