What color are the clouds?
The clouds are gray.
    src        edge_attr  dst
0     0   to the left of    4
1     1   to the left of   12
2     1   to the left of   11
3     3  to the right of    4
4     3   to the left of    8
5     4  to the right of    0
6     4   to the left of    3
7     6  to the right of    8
8     8   to the left of    6
9     8  to the right of    3
10    9  to the right of   10
11   10  to the right of   11
12   10   to the left of    9
13   10  to the right of   12
14   11  to the right of    1
15   11   to the left of   10
16   12   to the left of   10
17   12  to the right of    1