This is a friendship game NetLogo game model. A friendship game is a kind of network game: a game theory model on a network. A game starts with a model of a network of turtles. Each turtle considers as its friends every other turtle that is linked directly on the network. Each turtle decides what strategy to play, x or y, based on the choices made by its friends. How the friends influence the choice depends on whether the game is one of strategic substitutes or strategic complements.
A strategic substitute is something that, if one of its friends is already doing it, a turtle has no reason to also do it. For example, if a turtle gets a pickup truck, all its friends can borrow it, so they have no need to buy one, too.
A strategic complement is something that, if a majority of its friends are doing it, a turtle will also do it. For example, if the majority of a turtles friends are using NetLogo, then the turtle has an incentive to also use NetLogo.
This project is based on friendhip game models introduced by PJ Lamberson in a presentation in the Agent-based Computation Economics sessions of the Eastern Economics Association conference in February 2011.