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