For this, a bistable multivibrator was used, or as it’s called in the world of digital logic and Minecraft circuits, an S-R flip-flop ... centered around a 555 timer chip.

With a 555 on the BOM, you never know what you’re going to get. With 40 of the versatile timer ... a JK flip flop. His initial design for the flip flop that would form the core of the circuit ...