Cellular Automata/Rule


 * special reversible rules
 * totalistic rules
 * XML and other exotic rules

Second order rules
transforming a second order rule of neighborhood size $$k$$ into a first order rule of neighborhood size $$2k-1$$

Clustering rules
or different symmetries
 * 1) input complement
 * 2) output complement
 * 3) reflection symmetry
 * 4) rotation smetry (2D) ?can be produced by reflection no it can not
 * 5) equivalence class

mix

 * http://groups.google.com/group/comp.theory.cell-automata/browse_thread/thread/eedd3e963691fda2/41f376c8b51455b2?q=clusters&rnum=5&hl=en#41f376c8b51455b2
 * http://groups.google.com/group/comp.theory.cell-automata/browse_frm/thread/2375d42de9f86ee1?tvc=1&q=clusters&hl=en
 * http://groups.google.com/group/comp.theory.cell-automata/browse_frm/thread/86b9db28b67edf1/c5aac90b816f8f32?q=symmetry&rnum=21&hl=en#c5aac90b816f8f32
 * http://groups.google.com/group/comp.theory.cell-automata/browse_frm/thread/3a24112941446717/1e809a7956a95529?q=symmetry&rnum=9&hl=en#1e809a7956a95529