This is the 16th post in the Exercises in Programming Style focus series. In the book, this chapter is called Actors. In software, the actor model is a very specific way to design code: The actor model in computer science is a mathematical model of concurrent computation that treats 'actors' as the universal primitives of concurrent computation. In response to a message that it receives, an actor can: make local decisions, create more actors, send more messages, and determine how to respond to th