What is the street made of?
The street is made of concrete.
    src        edge_attr  dst
0     0   on the side of   11
1     1  to the right of   15
2     1  to the right of    5
3     2   to the left of   15
4     2   to the left of   14
5     2   to the left of    9
6     3   to the left of   15
7     3   to the left of    9
8     3               on   15
9     3   to the left of    4
10    4  to the right of    3
11    5               on   11
12    5   to the left of    1
13    5               on   15
14    6   to the left of   15
15    6   to the left of    9
16    7  to the right of   15
17    9  to the right of    6
18    9  to the right of    3
19    9  to the right of    2
20   10               on    8
21   13   to the left of   15
22   14  to the right of    2
23   15  to the right of    3
24   15  to the right of    6
25   15  to the right of   13
26   15  to the right of    2
27   15   to the left of    7
28   15   to the left of    1