What is the device on top of the desk?
The device is a computer mouse.
    src        edge_attr  dst
0     0  to the right of    7
1     0      in front of    7
2     1   to the left of    6
3     2               by    0
4     2        on top of    4
5     2  to the right of    5
6     2               on    4
7     5        on top of    4
8     5   to the left of    2
9     5       sitting on    4
10    6  to the right of    1
11    7   to the left of    0
12    7           behind    0