Which material is the door of the store made of, glass or steel?
The door is made of glass.
    src        edge_attr  dst
0     0           behind    8
1     0               of    2
2     0   to the left of   11
3     0   to the left of    6
4     0   to the left of   10
5     0   to the left of    7
6     1   to the left of   12
7     2           behind   15
8     2           behind    8
9     4   to the left of   12
10    5               in    0
11    5  to the right of   14
12    5   to the left of    6
13    5   to the left of    9
14    5   to the left of   10
15    6  to the right of    0
16    6  to the right of    5
17    6   to the left of    7
18    6   to the left of   11
19    7  to the right of    9
20    7  to the right of    6
21    7  to the right of    0
22    8      in front of    0
23    8   to the left of   15
24    8      in front of    2
25    8               on    6
26    9   to the left of   10
27    9   to the left of   11
28    9  to the right of    5
29    9   to the left of    7
30    9               on    8
31   10   to the left of   11
32   10  to the right of    5
33   10  to the right of    9
34   10  to the right of    0
35   11               of    2
36   11  to the right of   10
37   11  to the right of    0
38   11  to the right of    6
39   11  to the right of    9
40   12  to the right of    4
41   12  to the right of    1
42   12   to the left of   15
43   14               in    2
44   14   to the left of    5
45   15      in front of    2
46   15  to the right of   12
47   15  to the right of    8
48   15               of    2