The theoretical framework behind this project has been accepted as an extended paper for the GameOn North America Conference 2009 in Atlanta. Below you can find a brief explanation. The paper can be found on my website: this link.
These feedback diagrams are intended to represent a game's internal economy and flow of resources. According to literature most, if not all, games have an internal economy and this economy plays a vital role in its emergent behavior. A game's economic system is dominated by the flow of resources. In games resources can be anything: from money and property in Monopoly, via ammo and health in first person shooters, to experience points and equipment in role playing games. Even more abstract aspects of games, such as skill level and strategic position can be modeled through the use of resources.
These are animated diagrams: you will need to click the start button to activate the diagram. When a diagram is running it cannot be edited, click the stop button before making any changes. You can experiment with the diagram below (you can click on red stars to actively redistribute resources)...
These diagrams are also dynamic: their settings can change over time. For example, resources can be spend to improve a source, or the number of resources in pool can negatively affect a converter.
The most basic elements of these feedback diagrams deal with the flow of resources. The resources themselves are represented by small colored circles that flow through the diagram. In games resources are produced by certain entities or actions, in the diagram these are represented by a Source. Actions that cause resources to be removed from the game are represented by a Drain. A Pool is place where resources are gathered. Usually a player or AI has some sort of influence on how to use the resources that are collected in a pool. Often resources can be sent along different paths from a pool. A Knot is a place where resources are immediately redistributed. Black lines connecting the elements represent the routes a resource can travel.
Apart from resources, sources, drains and pools, these diagram uses state information to communicate between the different elements. State is communicated by state connecters (dotted lines). These communicate a numeric value that corresponds to the number of resources that is currently on an entity.
Elements can fire, a source that fires produces a number of resources, a converter or a drain fires when it has gathered enough resources. Inhibitors links can prevent elements from firing. Normal inhibitors need to pull a resource from another element or prevent the first element from firing. State inhibitors only check if a state is one or more (and do not affect the number of resources pulled).