The author challenges the idea that once you start farming, you're stuck. He also talks about seasonal variations in life style - an important motif. And on another recurring theme, which is play. There's a whole wonderful section on play, kings,. If this book is very playful, i feel that youve even said that you and david began it in a kind of spirit of play. Why does play matter? And what does the fact that people tried things out without fully committing it. W why is that important?