In systems life cycle management (SLCM), a gap exists between the informal methodologies for systems development and the mathematical formalisms needed for the automatic validation of systems properties and correctness proofs. This paper presents a model based on finite state machines and its translation into Petri nets, a mathematical representation with the desired degree of provability in this context. We a rgue that the model effectively bridges the gap between the intuitive representation of development process es on one hand, and the formal model necessary for val idation on the other hand, by allowing users withou t scientific or technical background to represent the ir activities and all their key features using simp le automata, by applying a systems thinking approach t o problem solving, instead of having to express the model in a more complicated representation from the start. Also, this model shows very promising results in other domains routinely modelled as activities, using other formalisms, like business processes.