[Brett] had been intrigued by some of the attempts to bend hardware SPI to the will of the WS2811 — notably ... step-by-step description of how the circuit works (it’s not worth re-explaining ...

[Leo] looked at the WS2811 LED driver ... in concert — one to control the current and one to PWM the LED. The circuit he came up with is deceptively simple — just four transistors, a Schottky ...