Is the color of the sky gray?
Yes, the sky is gray.
    src        edge_attr  dst
0     2  to the right of    9
1     2  to the right of    3
2     2  to the right of   15
3     2  to the right of   10
4     3   to the left of   10
5     3   to the left of    2
6     8  to the right of   15
7     8               in    4
8     9   to the left of   10
9     9   to the left of    2
10   10  to the right of   15
11   10   to the left of    2
12   10  to the right of    9
13   10  to the right of    3
14   15   to the left of    2
15   15   to the left of    8
16   15   to the left of   10