Which color is the floor?
The floor is gray.
   src        edge_attr  dst
0    1   to the left of    5
1    1   to the left of    2
2    1  to the right of    7
3    2  to the right of    8
4    2  to the right of    1
5    3   to the left of    6
6    5  to the right of    1
7    6  to the right of    3
8    7   to the left of    1
9    8   to the left of    2