What vegetable is on the pizza?
The vegetable is a tomato.
    src        edge_attr  dst
0     0   to the left of    5
1     0             with    1
2     0               on   15
3     0   to the left of   11
4     1               on    0
5     1  to the right of   14
6     2               on    0
7     3               of    4
8     3  to the right of   11
9     3  to the right of   15
10    4  to the right of   11
11    4  to the right of   15
12    4               on    6
13    5           beside   15
14    5               on    6
15    5  to the right of    0
16    5  to the right of   12
17    7               on   15
18    7  to the right of   14
19    8      topped with    7
20    8               on   15
21    8  to the right of   14
22   11  to the right of    0
23   11   to the left of    3
24   11   to the left of    4
25   11               on   15
26   12   to the left of    5
27   12               on   15
28   13               on    6
29   14           beside   15
30   14   to the left of    7
31   14   to the left of    1
32   14   to the left of    8
33   15               on    6
34   15   to the left of    3
35   15   to the left of    4