Today's featured article
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| A Garden of Eden is a pattern that has no parents and thus can only occur in generation 0. The term was first used in connection with cellular automata by John W. Tukey, many years before Conway's Game of Life was conceived. It was known from the start that Gardens of Eden exist in Life because of a theorem by Edward Moore that guarantees their existence in a wide class of cellular automata. The first Garden of Eden was found by Roger Banks and the MIT group in 1971. It had a bounding box of size 33 × 9 and 226 cells. Jean Hardouin-Duparc found the second and third Gardens of Eden by computer search in 1973, which had bounding boxes of size 122 × 6 and 117 × 6. His goal was to find Gardens of Eden with minimal height. In April 2016, Steven Eker found a Garden of Eden fitting inside a 5 × 83 bounding box. It is known that no Gardens of Eden exist with height less than 4, but the question is still open for height 4.
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In the news
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- October 10: AlbertArmstain rebuilds an initial stage from Mitchell Riley's H-to-Gs into a Herschel-to-B-heptomino converter; Christopher D'Agostino notices that this is actually a known E-heptomino converter appended to a previously unknown Herschel-to-E converter, HRx93E -- which enables completely new Spartan Herschel conduits Rx155 and R194, among other things.
- October 10: Mitchell Riley's "LightCone" search program finds several new Spartan Herschel-to-glider converters.
- October 9: Entity Valkyrie adapts Kazyan's B29 spaceship recipe to construct a period-84 gun, with a considerable reduction in size and period from the previous B29 gun (which was period 148).
- October 9 Kazyan reduces the glider construction recipe for the B29 spaceship to 16 gliders, with an improvement to 15G by DroneBetter.
- October 7-8: vilc assembles an adjustable-period oblique spaceship based on (2,1)c/6 puffers and rakes, alternately building and then burning a (4, 2)c/6 bi-block fuse; the next day the spaceship is upgraded to an adjustable-period 48+24N forerake.
- October 4: Alex Greason finds a large number of reduced-cost glider syntheses by running an exhaustive search in "QuSrc" (a custom-modified version of QuFince) to inspect all possible 5-glider collisions with glider placements in a 15x15 bounding box.
- September 26: EvinZL notices that a catalyst used in one of Simon Ekstrom's H-to-Gs from July 29 solves a very long-standing limitation of the stable F171 conduit, reducing its repeat time from 227 ticks to as low as 120.
- September 14: Mitchell Riley finds Lx65 duplicator, a record-breaking elementary Herschel fanout device -- a stable Spartan variant of the known Lx65 conduit, which until now has generally needed sparker support.
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Did you know...
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- ... that even without using fixed-cost reverse caber tosser technology, some specific N-bit period-2 oscillators can be constructed for any even integer N using no more than 27 gliders, and for any odd integer N using no more than 29 gliders, using a temporary tubstretcher?
- ... that in 2022, a still life was found containing a finite region whose only predecessor is itself?
- ... that it was proved in the early 1970s that reflectorless rotating oscillators exist in Life, but none were found until 2018 when Adam P. Goucher completed the 0E0P metacell, and none could be run through a full cycle without specialized hardware until smaller ones were constructed in 2021?
- ... that there are currently known elementary spaceships with speeds c/7 and c/10 orthogonal, but none with c/8 or c/9?
- ... that there are currently known elementary spaceships with speeds c/7, c/8, and c/12 diagonal, but none with c/9, c/10 or c/11?
- ... that Karel's p177 is the highest-period known elementary oscillator with no external support?
- ... there were no known oscillators with period 43 without the use of adjustable glider loops before the discovery of the period-43 glider gun in September 2022?
- ... that without the use of Herschel loops or adjustable glider loops, there are no known oscillators with period 89?
- ... that small stable elementary pulse dividers have been found for multipliers of ×2, ×3, ×4, ×5, ×12, ×11 and ×(6n+4), but not for ×7?
- ... that with reverse caber-tosser universal constructor technology, it is possible to build any possible glider-constructible pattern, no matter what size, using only 15 gliders?
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Pattern collection
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| The LifeWiki contains one of the most comprehensive catalogues of patterns available on the internet. Within it you will find:
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