What is the color of the device that is not turned-off?
The computer monitor is black.
    src        edge_attr  dst
0     0     plugged into    1
1     1       sitting on    8
2     2   to the left of    6
3     4   to the left of    6
4     5  to the right of   12
5     5   to the left of    6
6     6  to the right of    5
7     6  to the right of    4
8     6  to the right of   10
9     6  to the right of    2
10    6  to the right of   11
11    9        on top of    1
12   10   to the left of    6
13   11   to the left of    6
14   11  to the right of   12
15   12        on top of    1
16   12   to the left of   11
17   12   to the left of    5
18   12        on top of    8