Execute: Putting that built to use to address the open questions, trialing a prototype, peforming lab and/or field testing, a proof of concept trial with customers are all examples of the execution phase. The point is to execute an activity the exercises an apparatus under investigation, collect data and feedback, perform analysis on that data and feedback inorder to address the key questions and goals defined during the Design phase which inevitably drives further iterations of the respective phases to refine each as more is learned and understood.