What type of vegetable is on top of the crust?
The vegetables are onions.
    src        edge_attr  dst
0     0        on top of    1
1     0  to the right of    9
2     0            above    9
3     0  to the right of    3
4     2               on    4
5     2   to the left of    6
6     2  to the right of   10
7     2  to the right of   11
8     3        on top of    1
9     3  to the right of    9
10    3   to the left of    0
11    4             near   10
12    5               on    4
13    6  to the right of    8
14    6  to the right of    2
15    8  to the right of   12
16    8   to the left of    6
17    9   to the left of    3
18    9            under    0
19    9   to the left of    0
20    9            below    0
21   10   to the left of    2
22   10          next to    4
23   10             near    4
24   10   to the left of   12
25   11               on   10
26   11   to the left of    2
27   12  to the right of   10
28   12   to the left of    8