Do the shelf and the floor have a different colors?
No, both the shelf and the floor are black.
    src        edge_attr  dst
0     0  to the right of   14
1     0        on top of    3
2     0   to the left of    5
3     1  to the right of   12
4     1   to the left of    5
5     1   to the left of   11
6     3   to the left of    5
7     3   to the left of   11
8     4  to the right of   15
9     4  to the right of   17
10    5  to the right of    1
11    5  to the right of    3
12    5  to the right of    0
13    5  to the right of    8
14    5  to the right of   10
15    5   to the left of    6
16    5  to the right of    9
17    5  to the right of    7
18    6  to the right of    5
19    6  to the right of   11
20    6  to the right of    7
21    7               by   17
22    7  to the right of    8
23    7  to the right of   13
24    7   to the left of    6
25    7   to the left of    5
26    8  to the right of   13
27    8   to the left of    7
28    8   to the left of    5
29    9   to the left of    5
30   10   to the left of    5
31   10  to the right of   16
32   11  to the right of    3
33   11  to the right of    1
34   11   to the left of    6
35   12               on    3
36   12   to the left of    1
37   13               on   17
38   13   to the left of    8
39   13   to the left of    7
40   14   to the left of    0
41   15   to the left of    4
42   16               on    3
43   16   to the left of   10
44   17               in    2
45   17   to the left of    4