What is the sidewalk made of?
The sidewalk is made of brick.
   src        edge_attr  dst
0    0  to the right of    2
1    0  to the right of    3
2    0  to the right of    4
3    2   to the left of    0
4    3               on    0
5    3   to the left of    0
6    4   to the left of    0