What do the sign and the post have in common?
The color, both the sign and the post are yellow.
    src        edge_attr  dst
0     0  to the right of    6
1     1   to the left of    6
2     1   to the left of    2
3     2  to the right of    1
4     2   to the left of    6
5     4   to the left of   11
6     5   to the left of    6
7     5  to the right of   11
8     6  to the right of    1
9     6   to the left of    0
10    6  to the right of    9
11    6  to the right of    2
12    6  to the right of    5
13    9  to the right of   11
14    9   to the left of    6
15   11   to the left of    9
16   11   to the left of    5
17   11  to the right of    4