Is there either a mirror or a fence in this image?
Yes, there is a fence.
    src        edge_attr  dst
0     0  to the right of    6
1     0   to the left of    9
2     0  to the right of    8
3     0  to the right of    5
4     0   to the left of   12
5     0  to the right of   13
6     0  to the right of    3
7     1  to the right of   12
8     2   to the left of   10
9     2  to the right of   15
10    3   to the left of   12
11    3   to the left of    0
12    5   to the left of    0
13    5   to the left of   13
14    5   to the left of    6
15    6  to the right of    8
16    6   to the left of   12
17    6  to the right of    5
18    6   to the left of    0
19    7   to the left of    9
20    8   to the left of    6
21    8   to the left of    0
22    9  to the right of   12
23    9  to the right of    7
24    9  to the right of    0
25   10  to the right of    2
26   10  to the right of   15
27   10  to the right of   16
28   12  to the right of    6
29   12   to the left of    1
30   12  to the right of    3
31   12  to the right of   13
32   12  to the right of    0
33   12   to the left of    9
34   13  to the right of    5
35   13   to the left of   12
36   13   to the left of    0
37   15   to the left of    2
38   15   to the left of   10
39   15   to the left of   16
40   16   to the left of   10
41   16  to the right of   15