This document discusses using game design principles and mechanics to change behaviors through persuasive and rhetorical means. It summarizes that rhetorical design uses rules, interactions and representations to change how users think and act, similar to how games work. The document outlines different gameful design approaches like facilitating behaviors, sparking initial motivation or signaling to existing motivated users. It argues gameful design can rehearse plausible futures or embed persuasive arguments through procedural rhetoric in rule systems. The goal is to motivate behavior change through enjoyable gameplay rather than just extrinsic rewards.