What is the sidewalk made of?
The side walk is made of brick.
    src        edge_attr  dst
0     0   to the left of    8
1     0   to the left of   13
2     0   to the left of    1
3     0   to the left of   11
4     0  to the right of    5
5     0   to the left of    4
6     0   to the left of    2
7     1  to the right of    0
8     1  to the right of    2
9     1               on   10
10    1  to the right of   12
11    1   to the left of    4
12    1  to the right of   13
13    1  to the right of    8
14    2   to the left of    4
15    2  to the right of   12
16    2  to the right of    0
17    2   to the left of    1
18    3  to the right of    9
19    3   to the left of   11
20    3   to the left of    4
21    4  to the right of   10
22    4  to the right of   11
23    4  to the right of    3
24    4  to the right of   13
25    4  to the right of    2
26    4  to the right of    1
27    4  to the right of   12
28    4  to the right of    0
29    5   to the left of    0
30    5   to the left of   12
31    8  to the right of    0
32    8  to the right of   12
33    8   to the left of    1
34    9   to the left of    3
35   10   to the left of    4
36   11   to the left of    4
37   11  to the right of    3
38   11  to the right of    0
39   11  to the right of   12
40   12  to the right of    5
41   12   to the left of   13
42   12   to the left of    8
43   12   to the left of   11
44   12   to the left of    1
45   12   to the left of    4
46   12   to the left of    2
47   13  to the right of    0
48   13  to the right of   12
49   13   to the left of    1
50   13   to the left of    4