Do you think the floor is gray?
No, the floor is dark.
    src        edge_attr  dst
0     0  to the right of   12
1     1  to the right of    3
2     1   to the left of    9
3     2  to the right of   10
4     3   to the left of    1
5     4  to the right of   12
6     9  to the right of    1
7    10   to the left of    2
8    10  to the right of   12
9    12   to the left of   10
10   12   to the left of    4
11   12   to the left of    0