I'm designing a city at the moment and I want residential construction to follow an iterative design. Houses are made of connecting hexagonal rooms.
Families grow very large in my city due to some unrelated social things and construction is often done by residents. So the rules need to be simple enough to be understood by the general population and executed using only ruler and compass, in a reasonable amount of time(no huge algorithms that need a computer to execute). This ruleset needs to leave a minimum of 2 meters of space between houses(for walking and cycling). There can be no collisions, overlaps, or entrapments(a slow growing family shouldn't get trapped by their faster-growing neighbors).
The only solutions I've come up with result in an incredibly regular and boring city and can't handle irregularities of any form. I want my city to have an organic/fractal quality to it.