Is the fence black and long?
Yes, the fence is black and long.
    src        edge_attr  dst
0     0   to the left of   15
1     0   to the left of    8
2     1   to the left of    7
3     3  to the right of   10
4     4   to the left of   11
5     5       walking on   16
6     6   to the left of   12
7     6   to the left of    9
8     7  to the right of   10
9     7  to the right of    1
10    8  to the right of    0
11    9               on   12
12    9  to the right of    6
13   10   to the left of    7
14   10   to the left of    3
15   11  to the right of    4
16   11  to the right of   16
17   12  to the right of    6
18   15               on    7
19   15  to the right of    0
20   16   to the left of   11