What holds the white sign?
The chain holds the sign.
    src        edge_attr  dst
0     0               on    3
1     0  to the right of   18
2     0  to the right of    3
3     0  to the right of    9
4     0  to the right of    5
5     1   to the left of    2
6     2  to the right of    1
7     2  to the right of    3
8     3   to the left of    7
9     3   to the left of   15
10    3   to the left of    8
11    3   to the left of   16
12    3   to the left of    0
13    3   to the left of   12
14    3   to the left of    2
15    3   to the left of   14
16    3   to the left of    4
17    3   to the left of   13
18    3   to the left of   20
19    3   to the left of   17
20    4  to the right of    3
21    5  to the right of    9
22    5   to the left of    0
23    5   to the left of   16
24    5   to the left of    7
25    6   to the left of   14
26    6   to the left of   16
27    6  to the right of    9
28    7  to the right of   13
29    7  to the right of    3
30    7  to the right of    5
31    8  to the right of    3
32    8  to the right of   15
33    9   to the left of    0
34    9   to the left of   16
35    9   to the left of    5
36    9   to the left of   18
37    9   to the left of    6
38   11          holding   10
39   12  to the right of    3
40   13  to the right of    3
41   13   to the left of    7
42   14  to the right of    3
43   14  to the right of    6
44   15               on   12
45   15  to the right of    3
46   15   to the left of    8
47   16  to the right of   19
48   16  to the right of    3
49   16  to the right of   18
50   16  to the right of    9
51   16  to the right of    6
52   16  to the right of    5
53   17  to the right of    3
54   18   on the side of   19
55   18   to the left of    0
56   18  to the right of    9
57   18   to the left of   16
58   19   to the left of   16
59   20  to the right of    3