Circa late 1980s I remember our dad brought home a degauser from work, hey anyone remember what a degauser is? It was a magnetic box (VERY STRONG MAGNETS) with a tunnel to slide a cassette tape through, to erase the cassette tape. Well I don't remember which of us family members decided its storage place should be on top of the TV but what a fun science lesson that turned out to be 😄 If you moved the magnet around the TV in all different places, the distortion on the screen would follow wherever the magnet was, and IIRC the screen distortion wasn't permanent. The screen went back to normal when you removed the magnet from the vicinity.