OCA:EightLife

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EightLife
EightLife rule
Rulestring 238/3
B3/S238
Rule integer 137224
Character Chaotic
Black/white reversal B123478/S01234678

EightLife (or Pulsar Life) is a Life-like cellular automaton in which cells survive from one generation to the next if they have 2, 3 or 8 neighbours, and are born if they have 3 neighbours.

Patterns

Many patterns from regular Life are compatible with this rule. This is because EightLife is the most similar rule to Life, as cells are more likely to be off than on, and this rule requires a 3×3 square of on cells for an evolutionary difference, the least likely arrangement. Despite this, some patterns, like the heavyweight spaceship, do not survive. Pulsars are common, as the name "Pulsar Life" suggests, evolving from the pi heptomino. Honeycombs are also common, because a common spark in Life (specifically that of a lone table, the one hassled in worker bee) evolves into this pattern instead. The pentadecathlon evolves differently in a few phases but is still period 15 and retains its domino spark.

Universality

The universality of EightLife was mentioned in a poor quality article,[1] but the first true proof was published on the ConwayLife forums[2] in the form of a Rule 110 unit cell, which was inherited from Conway's Game of Life and constructed by Jason Summers.[3]

On November 21, 2017, Peter Naszvadi constructed another Rule 110 unit cell in Eightlife.[4] The pattern is based on eater 1, middleweight spaceship, twin bees shuttle and p46 gliderless MWSS gun, therefore it also applies to Pedestrian Life and HoneyLife.

References

  1. Francisco José Soler Gil, Manuel Alfonesca (July 2013). "Fine tuning explained? Multiverses and cellular automata". Journal for General Philosophy of Science. Retrieved on January 21, 2017.
  2. Peter Naszvadi (December 12, 2016). List of the Turing-complete totalistic life-like CA (discussion thread) at the ConwayLife.com forums
  3. Heinrich Koenig (December 21, 2005). ""Rule 110" Unit Cell". Game of Life News. Retrieved on January 21, 2017.
  4. Peter Naszvadi (November 21, 2017). FWSS-less MWSS-track-only Rule-110 Unit Cell (discussion thread) at the ConwayLife.com forums

External links

  • B3/S238 (discussion thread) at the ConwayLife.com forums