Spatial Prisoner's Dilemma

In the video below I show how to implement the Spatial Prisoner's Dilemma in NetLogo. This game, and variations of it, is often studied as it is a good model of how 'traits' might move through a population. Note that the 'space' need not be physical: it could be a social network (where the space is how close people are to each other), a computer network (hops), etc.