What are Cellular Automata (CAs)?

• A connected network of cells (usually 2D), i.e. discrete space
  
  
• Time is discrete as well
  
  
• Interactions are strictly local
  
  
• Each cell can be in one of a number of pre-defined states
  
  
• At each time-step, the new state of a cell is determined from its existing state and the states of its neighbours, via an explicit mapping (the transition function or rule table)
  
  
• Some variations (non-uniform rules, asynchronous updates, etc.)