What's the fence in front of?
The fence is in front of the sign.
    src        edge_attr  dst
0     0   to the left of   11
1     0   to the left of    6
2     0      in front of    3
3     3           behind    0
4     3   to the left of   13
5     3  to the right of   10
6     4  to the right of   17
7     4  to the right of   11
8     4  to the right of   16
9     4  to the right of   13
10    6  to the right of   11
11    6   to the left of   14
12    6  to the right of   13
13    6  to the right of   17
14    6  to the right of   16
15    6  to the right of    0
16    7   to the left of   13
17    8  to the right of   11
18    8   to the left of   14
19    9   to the left of   13
20    9  to the right of   10
21   10   to the left of    9
22   10   to the left of   13
23   10   to the left of    3
24   11  to the right of   16
25   11  to the right of    0
26   11   to the left of   15
27   11   to the left of    8
28   11   to the left of    4
29   11   to the left of    6
30   11  to the right of   13
31   11   to the left of   14
32   13  to the right of    3
33   13   to the left of    6
34   13   to the left of    4
35   13  to the right of    7
36   13   to the left of   17
37   13   to the left of   11
38   13  to the right of   10
39   13  to the right of    9
40   14  to the right of   11
41   14  to the right of   15
42   14  to the right of    8
43   14  to the right of    6
44   15   to the left of   14
45   15  to the right of   11
46   16   to the left of   11
47   16   to the left of    4
48   16   to the left of    6
49   17   to the left of    6
50   17  to the right of   13
51   17   to the left of    4