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