What is on the plate?
The broccoli is on the plate.
    src        edge_attr  dst
0     0               on    1
1     2               on    1
2     2  to the right of    6
3     2  to the right of    4
4     3               on    1
5     4               on    1
6     4  to the right of    6
7     4   to the left of    2
8     5               on    1
9     6   to the left of    4
10    6   to the left of    2