system
Given the following post, respond as if you're commenting on Reddit:
human
Why does brushing my teeth with an electric brush alter only specific light?

Specifically, when I am brushing my teeth with an electric toothbrush and I look at the LCD's on my alarm clocks, the numbers "dance". If I am across the room there is almost a centimeter of oscillation in the digits. What I don't understand is the clock, and the rest of the room is not affected at all. This happens on both clocks, one red light, one green.
gpt
The LCDs are flickering out of phase with the frequency that your skull is vibrating due to the toothbrush.  The rest of the lighting does not flicker, and so the same stroboscopic phenomena does not occur.