Do you see either fences or cones there?
Yes, there is a fence.
    src        edge_attr  dst
0     2  to the right of    6
1     2  to the right of    9
2     2  to the right of   13
3     2  to the right of    7
4     4   to the left of   13
5     4   to the left of    9
6     6   to the left of    2
7     7  to the right of    9
8     7   to the left of    2
9     7  to the right of   13
10    9  to the right of    4
11    9   to the left of    2
12    9   to the left of   13
13    9   to the left of    7
14   13   to the left of    2
15   13  to the right of    9
16   13   to the left of    7
17   13  to the right of    4