Here is a simple script to create a wavy washer, also known as a wavy spring.
(This can also be done with sine wave script, and Flow to a circle, with the correct vertical orientation.)
The script can be run twice with different radius, or offset, then do a loft and extrude.

Neat!

Cool!

Made another simple script. Have not grasped the math much yet.
The start and end points do not align, because they end with a control point, without another control point to bend the
curve to match. So part of the end and beginning of the curve can be deleted, to get rid this.