The sky is what color?
The sky is gray.
    src        edge_attr  dst
0     1  to the right of   12
1     3   to the left of    7
2     5  to the right of   16
3     7  to the right of    3
4     8  to the right of   16
5     9  to the right of   15
6    12   to the left of    1
7    15  to the right of   16
8    15   to the left of    9
9    16   to the left of    5
10   16   to the left of    8
11   16   to the left of   15