Seeds
Seeds  


View animated image  
Rulestring  /2 B2/S 


Rule integer  4  
Character  Explosive  
Black/white reversal  B012345678/S01234578 
Seeds is a lifelike cellular automaton in which only dead cells with exactly two live neighbors will turn into live cells on the next generation. Even though all the living cells are die in every generation (turning every pattern into a phoenix), most patterns are still exploding quadratically.
Contents
Notable patterns
Oscillators
It is obvious that no still lifes can exist in this rule. Known oscillator periods include 2, 3, 4, and 6. The five smallest ones are duoplet (2 cells, p2), shiplet (3 cells, p2), radar (4 cells, p4), lever (4 cells, p4) and anchor (4 cells, p4).
Spaceships
With B2, the Seeds rule allows spaceships to travel at the speed of light. The three smallest ones, known as photons, have a period of 1 and consist of only 4 cells each. Larger lightspeed spaceships with higher periods are also known.
There also exist c/2 and c/5 orthogonal spaceships and c/3 and c/4 diagonal spaceships.
Guns
Two period4 photon guns (lasers) have been found, yet their photon stream is too dense to implement any signal logic.
Puffers, Rakes and Breeders
Quite a lot of progress has been made in producing engineered patterns consisting of lightspeed puffers and photon rakes. A rake puffer breeder is known.
External links
 A collection of patterns for the Seeds rule; collected by Jason Summers, includes patterns found by Stephen Wright, Mirek Wójtowicz, Noam Elkies, Mark Niemiec, Peter Naszvadi, and David Eppstein.