I've got a half-cooked blog post about this in the oven: "reify the state machine". I've seen plenty of code with lots of communicating parts, which is really a

I've got a half-cooked blog post about this in the oven: "reify the state machine". I've seen plenty of code with lots of communicating parts, which is really a distributed implementation of a state machine. Rewriting to make the states explicit as data, and perhaps creating a central "state machine" type for that machine, can really help clarify the domain model and let you see what you're missing.