Is the ground metallic or wooden?
The ground is wooden.
    src        edge_attr  dst
0     0             near    1
1     1          next to    0
2     3   to the left of    9
3     4   to the left of   11
4     4               on    2
5     4   to the left of   10
6     6   to the left of    7
7     7  to the right of    6
8     8  to the right of   14
9     9  to the right of    3
10    9           behind   10
11   10      in front of    9
12   10   to the left of   11
13   10  to the right of    4
14   11               on    2
15   11  to the right of    4
16   11  to the right of   10
17   13  to the right of   16
18   13  to the right of   14
19   14   to the left of   13
20   14   to the left of    8
21   16   to the left of   13