Which kind of device is on top of the desk?
The device is a monitor.
    src        edge_attr  dst
0     0      in front of    6
1     1        on top of    0
2     1      in front of    6
3     1      in front of    3
4     1  to the right of   13
5     1   to the left of    3
6     1  to the right of    9
7     1   to the left of    4
8     2  to the right of    6
9     2       mounted on    5
10    3           behind    1
11    3  to the right of    1
12    4  to the right of    1
13    4  to the right of    6
14    4   to the left of   10
15    5   to the left of   10
16    5  to the right of    6
17    6           behind    1
18    6   to the left of    2
19    6   to the left of    5
20    6   to the left of    4
21    6  to the right of   12
22    6  to the right of    9
23    6   to the left of   10
24    6           behind    0
25    7   to the left of   11
26    7  to the right of    8
27    7        on top of    0
28    7  to the right of   13
29    8       sitting on    0
30    8        on top of    0
31    8  to the right of   13
32    8   to the left of    7
33    9   to the left of    1
34    9   to the left of    6
35   10  to the right of    6
36   10  to the right of    4
37   10  to the right of    5
38   11            under   11
39   11  to the right of    7
40   11        on top of   11
41   11            above   11
42   12   to the left of    6
43   13   to the left of    1
44   13   to the left of    7
45   13   to the left of    8