What is common to the sign and the box?
The color, both the sign and the box are red.
    src        edge_attr  dst
0     1  to the right of    6
1     1  to the right of   10
2     1  to the right of    9
3     2      in front of    3
4     2  to the right of    4
5     2   to the left of    7
6     3      in front of    4
7     3           behind    2
8     4   to the left of    2
9     4           behind    3
10    6   to the left of    1
11    7  to the right of    2
12    7  to the right of   10
13    9   to the left of    1
14   10   to the left of    7
15   10   to the left of    1