wire winder for tangle-free figure-8 winding

Avoid twists and tangles by winding with a figure eight pattern.  Scale print as desired.  I recommend PETG over PLA to avoid warping with usage in hot weather.

October 2022: revised model to remove one hole (the original version broke inside my backpack during some rough handling) and to resize.

Note that the gcode file is for a 0.6 mm nozzle with PETG.