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