How's the weather?
It is clear.
    src        edge_attr  dst
0     1   to the left of   16
1     1   to the left of    8
2     3  to the right of   12
3     4  to the right of   12
4     5   to the left of   10
5     6  to the right of   12
6     7       covered by   21
7     8  to the right of   19
8     8  to the right of    1
9     8               on   16
10    9  to the right of   14
11   10  to the right of    5
12   10  to the right of   12
13   11               on   19
14   11   to the left of   16
15   12   to the left of    4
16   12   to the left of    6
17   12   to the left of   10
18   12   to the left of    3
19   14   to the left of   17
20   14       covered in    3
21   14   to the left of    9
22   16  to the right of   11
23   16  to the right of    1
24   16  to the right of   19
25   17  to the right of   14
26   19   to the left of    8
27   19   to the left of   16
28   21         covering    7