What is the box on?
The box is on the sign.
    src        edge_attr  dst
0     0   to the left of    1
1     0   to the left of    8
2     0   to the left of   11
3     1  to the right of    0
4     1   to the left of    5
5     3   to the left of   11
6     3   to the left of    8
7     4               on    3
8     4   to the left of   11
9     4   to the left of    8
10    5  to the right of    1
11    5               on   11
12    6  to the right of   10
13    6  to the right of    7
14    7   to the left of   10
15    7   to the left of    6
16    7   to the left of    9
17    7   to the left of   12
18    8               on   12
19    8  to the right of    0
20    8  to the right of    3
21    8  to the right of    4
22    9  to the right of   10
23    9  to the right of    7
24   10   to the left of    9
25   10  to the right of    7
26   10   to the left of    6
27   10   to the left of   12
28   11  to the right of    3
29   11  to the right of    4
30   11  to the right of    0
31   12               on    0
32   12  to the right of   10
33   12  to the right of    7