In this paper we propose a diagrammatic framework, as a way of performing spatial reasoning about dynamic scenarios. Our proposal is based on intrinsically dynamic models, that act as some sort of mental simulation, a "mental movie" of the evolution of the represented world. This simulation is generated starting from some reference "pictures," or "snapshots" of the represented situation (that we call icons). Icons are interpolated by suitable generative processes, and they drive the dynamic simulation. The mechanism that interpolates icons in mental simulations is based on the model of artificiaL potential fields (APFs) APFs are a well-known method used for motion planning in Robotics. We show that the use of APFs can be extended to different domains, in order to face various problems of spatial reasoning and planning. In the paper we present our method by describing and discussing a series of examples, concerning both spatial reasoning and the interaction of reasoning with perception.