Blue cooperators, red defectors.
Credits:
Code based on Serge Helfrich's Java applet, with a fix for the minor problem in his version that cooperators get an extra point by cooperating with themselves.
More information on the game theory involved available from Wikipedia and VirtualLabs.
World maps based on Geonames Feature Density Map.
Map conversion with G.Projector.
Julia Set from Wikipedia.
Fractal Tree by Matthew James Taylor using Toby Schachman's RecursiveDrawing.com.
Brain from Wikipedia.
White House West Wing from Wikipedia.
Calcutta streetmap detail from Openstreetmaps.