What is the ground made of?
The ground is made of brick.
    src        edge_attr  dst
0     3      in front of   12
1     6  to the right of    8
2     8   to the left of    6
3     8   to the left of   13
4    11               on    3
5    11          wearing   10
6    11          wearing    7
7    11          wearing    0
8    11          wearing    2
9    11       sitting on    3
10   11          wearing    1
11   11          wearing    8
12   11          wearing    5
13   11          wearing    9
14   12           behind    3
15   13  to the right of    8