by Sebastian_09 on 7/27/22, 1:04 PM with 1 comments
by dalke on 7/27/22, 1:50 PM
It appears that if you have four rods in a 2×2 formation, then the interior part was called a squircle in one paper.
There's also a "squircle" in Struble’s 1962 book “Nonlinear differential equations”, page 39.
See that link for more details.
While I didn't mention it, there was also a non-mathematical use of "squircle" as a magic trick to turn a square into a circle.