What is the color of the clear sky?
The sky is blue.
    src        edge_attr  dst
0     1   to the left of    4
1     1   to the left of    7
2     1   to the left of    6
3     3  to the right of    5
4     4       hanging on    6
5     4  to the right of    1
6     5  to the right of    9
7     5  to the right of    6
8     5   to the left of    3
9     5  to the right of    8
10    5  to the right of    7
11    6   to the left of    5
12    6  to the right of    1
13    6   to the left of    9
14    6   to the left of    8
15    7  to the right of    1
16    7   to the left of    5
17    7   to the left of    9
18    7   to the left of    8
19    8  to the right of    7
20    8  to the right of    6
21    8   to the left of    5
22    9   to the left of    5
23    9  to the right of    7
24    9  to the right of    6