Do you see any fence that is not blue?
No, there is a fence but it is blue.
    src        edge_attr  dst
0     0   to the left of    3
1     0  to the right of    1
2     0   to the left of    4
3     0   to the left of   13
4     0  to the right of    7
5     0   to the left of    2
6     1   to the left of    0
7     1   to the left of    2
8     1   to the left of    3
9     1   to the left of   13
10    2  to the right of    0
11    2  to the right of    1
12    2   to the left of    9
13    2   to the left of   15
14    2  to the right of   11
15    3  to the right of   11
16    3  to the right of    1
17    3   to the left of   15
18    3  to the right of    0
19    3   to the left of    9
20    4  to the right of   11
21    4  to the right of    0
22    4  to the right of    7
23    6  to the right of   11
24    6   to the left of    8
25    7   to the left of    4
26    7   to the left of    0
27    8  to the right of   11
28    8  to the right of    6
29    9  to the right of    3
30    9  to the right of    2
31    9  to the right of   11
32   11   to the left of    8
33   11   to the left of    3
34   11   to the left of    4
35   11   to the left of   15
36   11   to the left of    2
37   11   to the left of   13
38   11   to the left of    9
39   11   to the left of    6
40   12               on   14
41   13  to the right of   11
42   13  to the right of    0
43   13  to the right of    1
44   15  to the right of    2
45   15  to the right of   11
46   15  to the right of    3