What is located on top of the cake?
The flower is on top of the cake.
    src        edge_attr  dst
0     0   to the left of    3
1     2   to the left of    6
2     2             near    6
3     3  to the right of    0
4     4        on top of    6
5     4               on    6
6     6        on top of    5
7     6      in front of    7
8     6               on    5
9     6             near    2
10    6  to the right of    2
11    6               on    1
12    7           behind    6