I think it's more like a Moore state-machine, coupled with some invariant functions. The events come in, and they alter the internal state somewhat thereby alte

I think it's more like a Moore state-machine, coupled with some invariant functions. The events come in, and they alter the internal state somewhat thereby altering future outputs elicited by similar events, but the invariant functions mean that certain things will never change over time. Of course, as with any real-world system at operational limits unpredictable behaviour can emerge.