What is the color of the sky?
The sky is gray.
    src        edge_attr  dst
0     0      surrounding   11
1     0            below    2
2     2  to the right of    6
3     2   to the left of    3
4     2   to the left of    5
5     2   to the left of    4
6     3  to the right of    2
7     4  to the right of    2
8     4  to the right of    6
9     5  to the right of    6
10    5  to the right of    2
11    6   to the left of    2
12    6   to the left of    4
13    6   to the left of    5
14    6   to the left of   11
15    8           behind   10
16   10      in front of    8
17   11        on top of    0
18   11    surrounded by    0
19   11  to the right of    6