This week's featured article

2×2 is a Lifelike cellular automaton in which cells survive from one generation to the next if they have 1, 2 or 5 neighbours, and are born if they have 3 or 6 neighbours. That is, it is governed by the rulestring "B36/S125". Patterns under the rule have a chaotic evolution similar to those under the standard Life rules, but the chaos tends to die out much more quickly.
The 2×2 rule gets its name from the fact that it can emulate a simpler cellular automaton that acts on each 2×2 block. The emulated automaton is a block cellular automaton that makes use of the Margolus neighbourhood. As a result, patterns that are originally made up of 2×2 blocks will forever be made up of 2×2 blocks, but the block partition will be offset by one cell in the odd generations from the even generations. There are 2^{12} = 4096 such Lifelike automata, of which 2×2 is the most wellknown.

Pattern collection

The LifeWiki contains one of the most comprehensive catalogues of patterns available on the internet. Within it you will find:


Did you know...

 ... that the smallest known sawtooth pattern in Conway's Life consists of only 177 ON cells?
 ... that there are now over a hundred and twenty known Herschel conduits, counting stable conduits only, and a much larger number if oscillatorsupported conduits are included?
 ... that Demonoids, caterloopillars, orthogonoids and halfbakery knightships are the only known types of spaceships with fixed slope but adjustable speed?
 ... that a pattern exists in which no cell in the unbounded Life plane ever becomes periodic?
 ... that several candidate universal constructors have been demonstrated in Conway’s Life, but as of June 2015 none have been formally proven to be universal?
 ... that there are dozens of known Cordership variants, including puffers, rakes and wickstretchers, with periods of any multiple of 96?
 ... that greyships have been constructed with speeds of c/2, c/3, c/4, c/5 and 2c/5?
 ... that most greyships travel parallel to the stripes in their included agars, but a few travel perpendicular to the stripes, or "against the grain"?
 ... that a pattern has been constructed that calculates and prints out the digits of pi in decimal, and a similar one prints out the decimal digits of the Golden Ratio?
 ... that several different patterns have been constructed to calculate and display the sequence of prime numbers, and some have been adapted to display only prime pairs or Fermat primes?

