Squircle

A squircle is a two-dimensional shape that sits between a square and a circle, its name blending the two words. The most common version is a superellipse defined by the equation absolute value of x minus a, raised to the fourth power, plus absolute value of y minus b, raised to the fourth power, equals r to the fourth power, where r is the radius and a and b give the center point; centered at the origin this curve is also called Lame quartic. A separate version called the Fernandez-Guasti squircle came out of optics research and uses a squareness parameter running from 0, giving a plain circle, to 1, giving a plain square, letting the shape move smoothly between the two without any point going to infinity. Squircles appear in practical design work such as dinner plates, device screens and app icons.