What's on the wall?
The tiles are on the wall.
    src        edge_attr  dst
0     0   to the left of    7
1     1  to the right of    9
2     1  to the right of    6
3     4  to the right of    7
4     5  to the right of    9
5     5               on    4
6     5               on    1
7     5               on    0
8     5               on    8
9     5               on    6
10    6   to the left of    1
11    6   to the left of    9
12    7  to the right of    0
13    7   to the left of    4
14    9   to the left of    5
15    9   to the left of    1
16    9  to the right of    6
17    9      attached to    7