Natural Sciences lecture series
Paul-Jean Letourneau describes his analysis of the behavior of rule 146
Rule 146 looks like a typical class-3 rule, and produces the same nested pattern as rule 90 when started with a simple initial condition. Sometimes, for certain types of initial conditions, there is a sudden phenomenon where, after a time, a large part of the evolution suddenly "dies". Paul-Jean has termed the appearance of this phenomenon a "monolith."
The appearance of a triangular region is caused by a run of cells of the same color (in this case, 0 cells) that then get eaten away from both sides, forming the triangle. By analyzing the frequency of various runs, a dumped probability distribution emerges. However, this distribution implies these monoliths are very rare, since they are composed of hundreds of zeros and hence have very low probability.
Perhaps most interesting is that these monoliths do not persist once they appear, and in fact diminish and eventually the density returns to the "equilibrium" level. Once they disappear, it has not been observed that the monoliths reappear again. The appearance of monoliths is dependent on the width of the system.
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