16: Creation and Recreation
Recreation is the primary way all life learns to achieve and thrive.

Exchange Principle: Playing and working to catalyze the ongoing activity of life.

17: Models and Currencies
At their deepest meaning, models and currencies are portals for connecting to each other. Yet all models are flawed lenses for realizing a world that we want.

Exchange Principle: Representing the flow of interaction and exchange to generate structure.

18: Tools and Weapons
All technology is knowledge energy transformed into physical matter.

Exchange Principle: Defining outcome of energy use makes it a tool or weapon.