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The length of the flexible strap that connects the two ends of the necklace behind the neck. Set to 0 for no strap.
The distance from one motor to the next. 3.20 cm is the original design; larger values lengthen the web between rings, smaller values shorten it (2.7 cm minimum, where the rings nearly touch).
Flat: the necklace laid out straight. Curved: wrapped into a loop, for Formlabs printers or a necklace longer than the print bed. Cone 45°: printed flat as a spiral that bends into a cone sloping 45° down from the neck when worn, with the strap on the inside and the hook on the outside.

Source, print settings and the inner motor ring on GitHub