What is located on top of the shelf?
The oranges are on top of the shelf.
    src        edge_attr  dst
0     0  to the right of    5
1     0               on   12
2     0          next to    4
3     0           behind    7
4     2   to the left of    6
5     4               on   12
6     4             near    0
7     4   to the left of   12
8     5   to the left of    0
9     6  to the right of    2
10    6  to the right of   10
11    6  to the right of   12
12    6               of   11
13    7          holding    9
14    7      in front of    0
15    9               on   12
16    9        on top of   12
17   10               on   12
18   10   to the left of   11
19   10   to the left of    6
20   11  to the right of   10
21   11  to the right of   12
22   12  to the right of    4
23   12   to the left of   11
24   12   to the left of    6