Abstract
The complex quadratic family z 7! z2 + c is well known to give rise to aesthetic images and renderings of Julia
sets—for a given complex number c, the Julia set is the boundary of the set of points z that escape to infinity under
iteration. There exists a unique critical value c, which is the image of the critical point z = 0. If iterates of c remain
bounded then the Julia set is connected, typically a set of closed (Jordan) curves, and if its iterations diverge to infinity
then the Julia set is a Cantor set. Here, we consider a non-analytic perturbation of the complex quadratic family and
its generalized Julia sets, which are defined in the same way. There are now infinitely many critical values that lie on
a circle. Consequently, some critical values may remain bounded under iteration, while others do not. Accordingly,
the (generalized) Julia set can be more complicated, leading to new intriguing mathematical objects that may provide
novel inspirations for art.
