Where do you think is the snow?
The snow is on the mountain.
    src        edge_attr  dst
0     1  to the right of    4
1     2               on    1
2     2   to the left of   12
3     3   to the left of   12
4     4   to the left of   12
5     4   to the left of    1
6     7               on    0
7     8  to the right of   10
8    10   to the left of    8
9    12  to the right of    3
10   12  to the right of    2
11   12  to the right of    4