“A representative customer, customer's representative, and/or knowledgeable user is involved on a continuing basis; involvement includes observation of periodic demonstrations of working, deliverable software at the ends of iterative development cycles that produce increments of working deliverable software (i.e., on a daily, weekly, bi-weekly, or monthly basis). In addition, a representative customer, customer's representative, or knowledgeable user provides guidance for further product development based on demonstrations of working deliverable software and the constraints on project scope (schedule, budget, and resources).”