CRESY-I stands for CREativity from a SYstems perspetive, Model I. This is the base model in a series designed to describe a systems approach to creativity in terms of variation, selection and retention (VSR) subprocesses. The general purpose of this model is to simulate the variation subprocess of creativity. It demonstrates the effects, in terms of emerging product domains, of stable creator types acting on the basis of behavioural variability, a theoretical continuum describing how differently (variable) an individual behaves or creates from time to time. An abstract model, CRESY-I was designed for theoretical exploration and hypotheses generation and theory development. It was programmed with NetLogo 4.1.