Familiar / Not Familiar

This looks like something you could find in the Mandelbrot set. But on a closer look you see it is something different.

Sequence fractals are not new. I came up with this idea 30+ years ago when I first started playing with fractals. I worked with it a little bit, and then moved on. There are so many other ways to mess up the standard fractal formula. All those other ways were calling for my attention. Occasionally, as here, I return to one of these early ideas and for a deeper look.