Which color does the bridge have?
The bridge has green color.
    src        edge_attr  dst
0     0  to the right of    7
1     1   to the left of    2
2     1      in front of    8
3     2  to the right of    7
4     2  to the right of    1
5     2   to the left of   16
6     2   to the left of    6
7     2               in    8
8     3  to the right of    6
9     3  to the right of   16
10    3               in    8
11    4            under    8
12    4            above   15
13    5               in   12
14    6  to the right of    2
15    6   to the left of    3
16    6      in front of    8
17    6   to the left of   16
18    7   to the left of    2
19    7   to the left of    0
20    8           behind    6
21    8            above    4
22    8         crossing    4
23    9               on    4
24   11               on   13
25   15            below    4
26   16   to the left of    3
27   16  to the right of    2
28   16  to the right of    6
29   16           inside    8