what is rule 146??
Rule 146 is an elementary class 3 cellular automaton rule. I think rule 146 is interesting because although its behavior seems largely random:
![An evolution of rule 146 from random initial conditions.](../images/rule146-no-particles.png)
… it may also be programmable via particle structures hidden in the evolution (highlighted here in red):
![Single particle propagating in rule 146.](../images/rule146-single-particle.png)
If rule 146 turns out to be generally programmable (i.e. if it could emulate a universal Turing machine), that would provide some (circumstantial) evidence that class 3 (random-looking) systems are generally programmable. See here for more on why this is actually kind of a deep problem.