What is before the star?
The tree is in front of the star.
    src        edge_attr  dst
0     0  to the right of    3
1     0  to the right of   15
2     0  to the right of    2
3     0  to the right of    4
4     0  to the right of   10
5     1   to the left of    7
6     1   to the left of    4
7     1   to the left of    3
8     1   to the left of   14
9     1  to the right of    9
10    1               on    6
11    1   to the left of    2
12    2      in front of    7
13    2   to the left of   10
14    2   to the left of    0
15    2   to the left of    8
16    2  to the right of    1
17    2               on   11
18    2               on    6
19    2  to the right of   13
20    3  to the right of    1
21    3   to the left of    0
22    3               on    1
23    4               on    2
24    4  to the right of    1
25    4   to the left of    0
26    4  to the right of    7
27    4   to the left of   10
28    5           behind    7
29    6   to the left of   11
30    7      in front of    5
31    7           behind    2
32    7   to the left of    4
33    7  to the right of    1
34    8  to the right of    2
35    9   to the left of    1
36    9   to the left of   15
37   10  to the right of    4
38   10  to the right of   15
39   10   to the left of    0
40   10  to the right of    2
41   11  to the right of   12
42   11  to the right of    6
43   12               on   11
44   12   to the left of   11
45   13   to the left of    2
46   13   to the left of   14
47   14  to the right of   13
48   14  to the right of    1
49   15               on    1
50   15   to the left of   10
51   15  to the right of    9
52   15   to the left of    0