What kind of food is on the tray?
The food is a sandwich.
    src        edge_attr  dst
0     2   to the left of    8
1     2   to the left of    4
2     4  to the right of    5
3     4  to the right of    2
4     5   to the left of    4
5     5   to the left of    8
6     6               on    7
7     6  to the right of    8
8     7  to the right of    8
9     8  to the right of    5
10    8   to the left of    6
11    8   to the left of    7
12    8               on    4
13    8  to the right of    2