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thank you!

this is simple tool for that
https://www.adafruit.com/product/1776

Me neither @vasil-danev! This is pretty cool indeed. I once tried this with my teacher waaay back. I remember waving some lightstick really quickly and trying to stay hidden behind what I wrote (my name). That project felt really mysterious at that time and to be honest this still feels and I would like to learn this technique!