Dual extrusion ... Extruders are swapped by moving the carriage to either end of the x-axis, where the v-wheel rolls a ramp and pops the rocker over, putting the new extruder in the center line ...

Pellet agitator is part of the extruder. All of this travels along with the print head. Take the extrusion screw. Like the homemade rotary encoders [HomoFaciens] is known for, it appears at first ...