What's the bridge made of?
The bridge is made of wood.
    src        edge_attr  dst
0     0  to the right of    6
1     0   to the left of    3
2     1   to the left of    4
3     3  to the right of    0
4     4  to the right of    1
5     4  to the right of    8
6     5  to the right of    6
7     6   to the left of    0
8     6   to the left of    5
9     8   to the left of    4
10    9               on    5