This divertimento – on the occasion of the 70th anniversary of
Prof., Dr Hermann Maurer
– sketches some observations over the concepts of domain, requirements and modelling – where abstract interpretations of these models cover both a priori, a posteriori and real-time aspects of the domain as well as 1–1, microscopic and macroscopic simulations, real-time monitoring and real-time monitoring & control of that domain. The reference frame for these concepts are domain models: carefully narrated and formally described domains. I survey more-or-less standard ideas of verifiable development and conjecture product families of demos, simulators, monitors and monitors & controllers – but now these “standard ideas” are recast in the context of core requirements prescriptions being “derived” from domain descriptions.