We can either chat about the 0.01% of scenarios ... or the other 99.99%. The other 99.99% look extremely similar ... it's towns not allowing two-family homes in one-family zones. Three-family homes in two-family or one-family zones. We're not even talking about apartment buildings. All of those are built using "variances", which just illustrate how absurd the system is.
Oh and speaking about your example? I live in a two-family home in a two-family zone ... next to a bus depot. How you ask? Well, they just got a variance I guess. ¯\_(ツ)_/¯