This week's featured article
|A still life is a pattern that does not change from one generation to the next, and thus may be thought of as an oscillator with period 1. Still lifes are sometimes assumed to be finite and non-empty. The two main subgroups of still lifes are strict still lifes and pseudo still lifes. In some contexts, the term "still life" may refer to strict still lifes.
A strict still life is a still life that is either connected (i.e., has no islands), or is such that removing one or more its islands destroys the stability of the pattern. For example, beehive with tail is a strict still life because it is connected, and table on table is a strict still life because neither of the tables are stable by themselves.
A pseudo still life consists of two or more islands which can be partitioned (either individually or as sets) into non-interacting subpatterns which are by themselves each still lifes. Furthermore, there must be at least one dead cell that has more than three alive neighbours in the overall pattern but has less than three alive neighbours in the subpatterns. This final restriction removes patterns such as bakery, blockade and fleet from consideration, as the islands are not "almost touching".
In the news
|The LifeWiki contains one of the most comprehensive catalogues of patterns available on the internet. Within it you will find:
Did you know...
- ... that an O(sqrt(log(t))) pattern was constructed in 2010, with a diameter that grows at the slowest possible asymptotic ("big O") rate for any Life pattern?
- ... that since the first Cordership was assembled from 13 switch engines in 1991, the number of switch engines required has gradually decreased, with a 2-engine Cordership finally making its appearance in 2017?
- ... that the bounding box and recovery time of the current fastest stable reflector, Mike Playle's Snark, are both more than two full orders of magnitude smaller than the first stable reflector, constructed by Paul Callahan in 1996?
- ... that as of 2019, no elementary replicators have been found in Life?
- ... that while multiple c/12 diagonal spaceships are known, none are true period?
- ... that the first p23 oscillator, David Hilbert, was created as a modification of a "troll" pattern posted a week earlier?
- ... that exactly two years after a fake loafer-producing soup was posted to the forums on April Fools' Day, a real soup was found on April 1, 2020?
- ... patterns have been constructed whose fate is currently unknown (based on the twin primes and Collatz conjectures)?
- ... a pattern of 44 cells exists whose population grows by exactly one cell each generation?
- ... it is possible to send a signal from one side to the other of an infinite diagonal line of cells without destroying the line?