Of which color is the sky?
The sky is blue.
    src        edge_attr  dst
0     0   to the left of    4
1     2   to the left of    4
2     3  to the right of    8
3     4  to the right of    2
4     4  to the right of    0
5     8   to the left of    3
6     8   to the left of   11
7     9               in    7
8    11   to the left of   12
9    11  to the right of    8
10   12  to the right of   11