Self-Organized States in Cellular Automata: Exact Solution
  The spatial structure, fluctuations as well as all state probabilities of self-organized (steady) states of cellular automata can be found (almost) exactly and {\em explicitly} from their Markovian dynamics. The method is shown on an example of a natural sand pile model with a gradient threshold. 
M.V. Medvedev (CfA), P.H. Diamond (UCSD)