Iterated function systems

In the display case between L-systems and classic fractals like the Mandelbrot set, we have IFSs. There is a lot of definitional overlap between these things; mostly the difference is about where they are used and the algorithms used to draw them.

• Why does no one (seem to) use linearized Gaussian error propagation to choose smoothing kernel size when rendering? It would reduce the number of iterations necessary to overpaint (I think it would; but there must be some reason no one does it?)
• Is there a meaningful acoustic equivalent?
• At some point, I would like to understand how the Barnsley IFS algorithm inferred IFSs from images.
• Construct IFS as a point process / branching process.