What is in front of the wall?
The graffiti is in front of the wall.
    src        edge_attr  dst
0     0   to the left of   11
1     0   to the left of   10
2     1   to the left of   10
3     2   to the left of   10
4     2  to the right of    8
5     3   to the left of   10
6     4           behind    6
7     5   to the left of   11
8     5   to the left of   10
9     6               on    4
10    6      in front of    4
11    8   to the left of    2
12    9   to the left of   10
13   10  to the right of    0
14   10  to the right of    1
15   10  to the right of    5
16   10  to the right of    2
17   10  to the right of    3
18   10  to the right of    9
19   11  to the right of    5
20   11  to the right of    0