This new node is based upon translated mathematica code.

arcLoop.js is a node which produces a planar closed curve made up of arcs and a line for a flat side. It can display circle, ellipse, "lens", and 4 sided "diamond" quad lens shape. It can also have one flat side. It may be considered a cross section in a forthcoming script. Place arcLoop.js in the nodeeditor expansion directory.
The arcLoopNodePgm.nod may be placed with other .nod files.

The helper function is placed near the top of the .js file, not in a separate functions file.

- Brian

This is NOT a squircle node.
Do not claim to understand the math.
Have not been able to locate such loops with google searches.