The integrated model of a perceptual-motor system described here is designed with a high priority given to the ability to combine a library of individual process algorithms into a simulation of a smoothly functioning complex behavior. There are, in addition, several fundamental psychological assumptions guiding our work that directly impact the organization and nature of the computer programs we are producing. For example, we explicitly assume that perceptual processes can be partitioned into a series of sequential steps, some of which may have some intrinsic parallel organization. We also assume that global organization (rather than local features) should be the basis of the most realistic model of perception.