Does the sign have a different color than the window frame?
Yes, the window frame is blue and the sign is white.
    src        edge_attr  dst
0     1               by    2
1     2               by    8
2     2               by    6
3     3   to the left of    7
4     3   to the left of   12
5     3   to the left of   10
6     3   to the left of   11
7     3   to the left of    4
8     4  to the right of    3
9     5  to the right of   11
10    6  to the right of   10
11    7  to the right of    3
12    7               on    3
13    8  to the right of   10
14    9  to the right of   10
15    9               on    2
16    9               on    8
17   10   to the left of    8
18   10   to the left of    9
19   10   to the left of    6
20   10  to the right of    3
21   11   to the left of    5
22   11  to the right of    3
23   12  to the right of    3
24   12               on    3