It's alive! Ender 3 Pro capable of 5-color print. 3-in-1 out hot end with 2 Y-merger piece. Stock board plus Arduino Uno+CNC shield all driven by Klipper on a Raspberry Pie 3B+. :
3D printing]Editing the printer.cfg file with Klipper part 3 - YouTube
Klipper (3D Printer Firmware): What Is It & How to Use It? | All3DP
Accessory Mode with Palette 3 - Mosaic Manufacturing