Do you see grass or sand that are not brown?
No, there is grass but it is brown.
    src        edge_attr  dst
0     2  to the right of   12
1     3   to the left of    5
2     3           behind    6
3     5               of    6
4     5  to the right of    3
5     6      in front of   10
6     6             near   13
7     6             near    7
8     6             near   14
9     6      in front of    3
10    7             near    6
11    8  to the right of   12
12    9             near   14
13   12   to the left of    8
14   12   to the left of    2
15   13             near    6
16   14             near    9
17   14             near    6