Plotting the Mandelbrot Set | Recursive LAMDBA and COMPLEX Functions in Excel

I've been trying to get my head around recursive functions for the last few weeks. I remain convinced that this is actually an undocumented feature rather than an intended use for LAMBDA(), but it works.
Anyway, here's how to plot a fractal in a spreadsheet. It actually calculates faster than you might expect, but it remains awkward -- and difficult because the COMPLEX() functions and IMSUM() and IMPOWER() don't play nicely with dynamic arrays. So here we are, trying to drag cells around like it's 2017 again. Eugh. Do it in in proper software. You know, like Lisp or whatever.