Are both the doors and the plates made of the same material?
No, the doors are made of glass and the plates are made of metal.
    src        edge_attr  dst
0     0   to the left of    9
1     1   to the left of   10
2     1   to the left of   11
3     1   to the left of   19
4     2   to the left of    9
5     3  to the right of   13
6     4  to the right of   19
7     4               on   12
8     9  to the right of    0
9     9  to the right of    2
10   10  to the right of   14
11   10  to the right of    1
12   10   to the left of   20
13   11  to the right of    1
14   11   to the left of   19
15   12  to the right of   20
16   12  to the right of   19
17   13            above   14
18   13   to the left of    3
19   14   to the left of   20
20   14   to the left of   10
21   14            below   13
22   16               on    2
23   18               on   17
24   19   to the left of    4
25   19   to the left of   12
26   19  to the right of    1
27   19  to the right of   11
28   20  to the right of   10
29   20   to the left of   12
30   20  to the right of   14