This is an example of very early computer art when computers were not at all what they are today. I plotted this function (a superposition of several harmonics in radial coordinates) in 1972 on one of the very first programmable table-top computers (a Hewlett-Packard) and I did it with the explicit goal of achieving a pleasing effect. And I kept it for over 30 years because I still like it. Which, I suppose, is what art is all about.

Stanislav Sykora, ink on paper, 28 x 22 cm