2 kinds of Julia set

The Julia sets of polynomials z³+c, for c varying along a curve, stacked on top of each other. The curve ends at 0, so the Julia set belonging to its endpoint is a circle. Then another curve starts at 0, this time defining Julia sets for polynomials of the form z²+c. The two kinds of Julia set stacks are glued together at theitr circular ends.
The polygonal approximations of the Julia sets have been computed for 14 backwards iterations.

A version which has more detail and uses less material, but cannot be printed in steel, is available here.
The lower half of this sculpture, hollowed out so that it can be used as a bowl, is available here.