But these were not your standard WS2812B strips with data lines ... using an ATMega328P as a controller and an ATtiny10 as the LED driver. With just a few lines of code and a 100 nF buffer ...

(Trust us, it’s a fruit.) With some research, he discovered the HT16K33 LED driver, which checked all the boxen. The first version worked, but needed what looks like a couple of bodge wires.