A housing development nearby my home was built in the early 1960s (I think). If you look closely at the homes, they are all of two designs, made into four by mirror images.

But it's pretty clear that over time the homes were remodeled, gut remodeled, extended, garages added, and so on, so they are significantly improved over the original. I've been in a couple, and the hallways are pretty narrow and everything is very cheaply built.

If you want to see what they were like originally, see the old Bob Hope movie "Bachelor in Paradise", filmed at a just-built suburban community.