Update: Version 2.0 of FractalBlocks is much faster, has better handling for out-of-range values, and features improved controls. Also, this tool can be found in Reactor, Fusion's free, community-built package manager.
After Effects has a very useful setting in its Fractal Noise effect that turns its output into blocks. Here is a macro that replicates most of that feature in Fusion.
It's a bit slow, and there are a couple of issues that I'll eventually iron out, as well as a couple more controls I'd like to add, but in its current form it solves the problems I wanted to solve.
MT stands for MuseTools, a collection of tools and elements created by and for Muse VFX.