What is in front of the wall that looks gray?
The bench is in front of the wall.
    src    edge_attr  dst
0     1         near    5
1     1           in    5
2     1        above    5
3     1  in front of    2
4     1        above    3
5     1         near    7
6     2       behind    1
7     4         near    5
8     4         near    7
9     5         near    4
10    5   underneath    1
11    5         near    1
12    7         near    4
13    7         near    1