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