What kind of device is on the wall?
The device is a projector.
    src        edge_attr  dst
0     0  to the right of    4
1     0   to the left of    9
2     0  to the right of   11
3     2  to the right of    5
4     4   to the left of    0
5     4  to the right of   11
6     4  to the right of    7
7     5   to the left of    2
8     5   to the left of    6
9     5   to the left of    9
10    6  to the right of    5
11    7   to the left of    4
12    9  to the right of    0
13    9  to the right of    5
14   10               on    9
15   11   to the left of    4
16   11   to the left of    0