The electromechanical television got me in trouble with my 5th grade teacher. When she stated that television dated to the 1940s, I (obnoxiously) had to correct her that in fact it was invented the late 1920s as I had seen one of the original Baird televisions in the British Museum.

I wish there was a photo of the writer's setup, I would love to see a modern version in action.

Here's a video of it in action: https://www.youtube.com/watch?v=41b8fw3_wP8

Oh, sort of like a LED wand.[1] Those were a popular toy for ravers a few decades back. Hard to find now.

[1] https://tinkersphere.com/soldering-level-i/3355-magic-messag...