What's on the roof?
The fence is on the roof.
    src        edge_attr  dst
0     1  to the right of    6
1     1  to the right of    5
2     3   to the left of    6
3     3               on   10
4     4   to the left of    6
5     4               of    9
6     4   to the left of    5
7     5   to the left of    1
8     5  to the right of    4
9     5  to the right of    9
10    6             with   13
11    6  to the right of   12
12    6  to the right of    4
13    6   to the left of    7
14    6  to the right of    9
15    6   to the left of    1
16    6  to the right of    3
17    7  to the right of    6
18    8        riding on    5
19    9   to the left of    6
20    9   to the left of    5
21   12   to the left of    6