What color is the bridge?
The bridge is gray.
    src        edge_attr  dst
0     1  to the right of    7
1     1  to the right of    6
2     1  to the right of    4
3     2             near    8
4     2             near    4
5     2            below    3
6     3            above    2
7     4          next to    2
8     4  to the right of    7
9     4   to the left of    1
10    5  to the right of    6
11    5               on    1
12    6   to the left of    5
13    6   to the left of    1
14    7               on    6
15    7   to the left of    4
16    7   to the left of    1
17    8             near    2