Do the sign and the sky have a different colors?
No, both the sign and the sky are white.
    src        edge_attr  dst
0     0   to the left of   15
1     1  to the right of   15
2     1  to the right of    8
3     2               of    8
4     2  to the right of    9
5     3   to the left of   10
6     3  to the right of   11
7     4  on the front of    8
8     4  to the right of    9
9     6  to the right of   12
10    6  to the right of   14
11    8   to the left of   13
12    8   to the left of    1
13    8            below    5
14    9   to the left of    4
15    9   to the left of    2
16   10  to the right of    3
17   11   to the left of    3
18   12  on the front of    8
19   12   to the left of    6
20   12   to the left of   16
21   13  to the right of   15
22   13  to the right of    8
23   14   to the left of   16
24   14   to the left of    6
25   15  to the right of    0
26   15   to the left of   13
27   15   to the left of    1
28   16  to the right of   12
29   16  to the right of   14