What's located on top of the salad?
The leaf is on top of the salad.
    src        edge_attr  dst
0     0               on    4
1     1               on    4
2     1   to the left of    6
3     1   to the left of    3
4     2               in    7
5     2            below    7
6     2            below    3
7     2            under    3
8     2               on    4
9     3  to the right of    1
10    3            above    2
11    4             near    8
12    6  to the right of    1
13    6        on top of    7
14    7               on    4
15    7            above    2
16    8          next to    4