Robert P. Munafo, 2003 Dec 30.
The more common type of rotational symmetry in the Mandelbrot set, involving two or more arms that spiral in to a point. Often the spiral is very subtle, as illustrated in the entry for R2F(1/3B*).
From the Mandelbrot Set Glossary and Encyclopedia, by Robert Munafo, (c) 1987-2017. Mu-ency index
This page was written in the "embarrassingly readable" markup language RHTF, and was last updated on 2017 Feb 02. s.11