What is in the terminal?
The truck is in the terminal.
    src        edge_attr  dst
0     2  to the right of    7
1     2  to the right of   10
2     3  to the right of    7
3     3  to the right of    4
4     4   to the left of    3
5     4  to the right of    7
6     4  to the right of    5
7     5   to the left of    4
8     5  to the right of   13
9     6               in   13
10    6  to the right of   13
11    7   to the left of    3
12    7   to the left of    9
13    7   to the left of    4
14    7   to the left of    2
15    9  to the right of   10
16    9  to the right of    7
17   10   to the left of    9
18   10   to the left of    2
19   13   to the left of    6
20   13   to the left of    5