Saturday, June 28, 2014

Alternating rules and knightships

Today I've added new feature to the Online simulator of reversible cellular automata: alternating rulesets. Now user can define several independent rules that will be alternated on each step. For example, if you define 2 rules, then automata will evolve according to the first rule on each even generation, and according to the second rule on each odd generation. All features, including pattern analyzer, work with alternating rulesets!

And the first little discovery is the combination of rules, that spontaneously produces knightships: a spaceships that move two cells horizontally for every one cell it moves vertically. The rule combination is SingleRotate/BounceGas,: [0,2,8,3,1,5,6,7,4,9,10,11,12,13,14,15]/[0,8,4,3,2,5,9,14,1,6,10,13,12,11,7,15]. Here are they:

RLE codePeriodSpeed
bo3bo$3b2o 238 (2,1)c/119
b2o$o3$bo 122 (2,1)c/61

And here is the animations, showing movement of these knightships:

Animated image of 2 knightships in the alternating rule SingleRotate/BounceGas. Try in the Simulator.

Simulator interface

To enable alternating rules, go to the "Rule details" pane, then click on the [+] button next to the rule entry. This will duplicate a rule, creating alternating set of rules.

When drawing new patterns or pasting patterns from the library, pay attention to the "Vacuum phase" field below the field. It shows number of the currently active rule from the ruleset, starting from 0. (When ruleset contains rules, turning empty field to non-empty, and "hide vacuum changes" checkbox is enabled, different ruleset with more rules will be enabled)