All the model topologies that have names are heuristics. The idea of a 'layer' is a heuristic. And so on. You don't really just try stuff. You choose very few

All the model topologies that have names are heuristics. The idea of a 'layer' is a heuristic. And so on. You don't really just try stuff. You choose very few things to try from the space of models. And you choose craftily. We have quite a lot of domain craftiness now, if you think about it that way.