Is there a helmet or a fence in the picture?
Yes, there is a fence.
    src        edge_attr  dst
0     0   to the left of   15
1     1   to the left of    3
2     1   to the left of   16
3     1   to the left of    2
4     2  to the right of   14
5     2               in    1
6     2  to the right of    1
7     2  to the right of    3
8     2  to the right of    8
9     3   to the left of   16
10    3   to the left of    2
11    3  to the right of    1
12    6               on    1
13    6   to the left of    9
14    6   to the left of    7
15    7  to the right of    6
16    7               on    1
17    8   to the left of   16
18    8   to the left of    2
19    9  to the right of    6
20   11            above   15
21   14   to the left of   16
22   14   to the left of    2
23   15  to the right of    0
24   16  to the right of   14
25   16  to the right of    8
26   16  to the right of    3
27   16  to the right of    1