What is the snow on?
The snow is on the roof.
    src        edge_attr  dst
0     0   to the left of    8
1     0  to the right of    9
2     5   to the left of    6
3     6  to the right of    5
4     6  to the right of    8
5     6  to the right of    7
6     7   to the left of    6
7     8       sitting on    7
8     8  to the right of    0
9     8   to the left of    6
10    8  to the right of    9
11    8  to the right of   11
12    8               on    7
13    9   to the left of    8
14    9   to the left of   11
15    9   to the left of    0
16   10               of    5
17   11  to the right of    9
18   11   to the left of    8
19   13               on    1