What material makes up the sidewalk?
The sidewalk is made of concrete.
    src        edge_attr  dst
0     1   to the left of    5
1     1   to the left of    2
2     2  to the right of    4
3     2  to the right of   12
4     2  to the right of   15
5     2  to the right of    6
6     2  to the right of    1
7     2  to the right of    7
8     4  to the right of    6
9     4   to the left of    7
10    4   to the left of    2
11    4   to the left of   12
12    4   to the left of   15
13    4          wearing    7
14    5  to the right of    1
15    5  to the right of    7
16    5  to the right of   12
17    6   to the left of    2
18    6   to the left of    7
19    6   to the left of   10
20    6   to the left of    4
21    6   to the left of   15
22    6   to the left of   12
23    7  to the right of    6
24    7   to the left of    5
25    7  to the right of    4
26    7   to the left of    2
27    7   to the left of   15
28    9               by    8
29   10  to the right of    6
30   10  to the right of   14
31   12  to the right of    4
32   12   to the left of    2
33   12  to the right of    6
34   12   to the left of    5
35   12   to the left of   15
36   14   to the left of   10
37   15  to the right of    4
38   15  to the right of    7
39   15  to the right of    6
40   15   to the left of    2
41   15               at   10
42   15  to the right of   12