Schelling's model of spatial segregation.
Schelling's model of spatial segregation is a milestone in the study of emergent global phenomena based on local social interactions (Schelling 1969; Schelling 1971; Schelling 1978). Schelling's model illustrates how clearly distinctive patterns of spatial segregation (e.g. ghettos) can emerge even if individuals are only weakly segregationist.
SCHELLING T C (1969) Models of Segregation. American Economic Review, 59(2), pp. 488-493.
SCHELLING T C (1971) Dynamic Models of Segregation. Journal of Mathematical Sociology, 1(2), pp. 143-186.
SCHELLING T C (1978) Micromotives and macrobehavior. New York: Norton.
For further details, have a look at the paper: "Techniques to Understand Computer Simulations: Markov Chain Analysis".