What kind of vehicle are the windows around of?
The windows are around the train car.
    src        edge_attr  dst
0     0  to the right of    6
1     0   to the left of    1
2     1  to the right of    0
3     3  to the right of    4
4     4  to the right of    5
5     4   to the left of    3
6     4  to the right of    7
7     4  to the right of   11
8     5   to the left of    4
9     5   to the left of    7
10    6   to the left of    0
11    6      standing on    9
12    7  to the right of    5
13    7   to the left of    4
14   11           around    5
15   11   to the left of    4