What is the tray made of?
The tray is made of plastic.
    src        edge_attr  dst
0     0   to the left of   15
1     1  to the right of    9
2     1  to the right of    4
3     1  to the right of    7
4     2   to the left of    8
5     2   to the left of   16
6     2   to the left of    9
7     2               on   11
8     2   to the left of    4
9     4   to the left of    1
10    4  to the right of    2
11    4  to the right of   10
12    4   to the left of    9
13    4  to the right of    7
14    5               in    6
15    5  to the right of    7
16    6               of    5
17    6  to the right of    7
18    7   to the left of    5
19    7   to the left of    6
20    7   to the left of    8
21    7   to the left of    1
22    7   to the left of    9
23    7   to the left of   16
24    7   to the left of    4
25    7   to the left of   12
26    8  to the right of   10
27    8  to the right of   15
28    8  to the right of    7
29    8  to the right of    2
30    8               on   11
31    9  to the right of    2
32    9   to the left of    1
33    9  to the right of    7
34    9  to the right of    4
35   10   to the left of   16
36   10   to the left of    4
37   10   to the left of    8
38   11             with   15
39   12  to the right of    7
40   13  to the right of   14
41   13   to the left of   15
42   14               on    7
43   14               in    6
44   14   to the left of   13
45   15  to the right of    0
46   15   to the left of    8
47   15  to the right of   13
48   15   to the left of   16
49   16  to the right of   15
50   16  to the right of    2
51   16  to the right of    7
52   16  to the right of   10