This week's featured article
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| Pentadecathlon is a period-15 oscillator that was found in 1970 by John Conway while tracking the history of short rows of cells (see one-cell-thick pattern). Indeed, 10 cells placed in a row quickly evolve into this object, which is the most natural oscillator of period greater than 3. In fact, it is the fifth or sixth most common oscillator overall, being about as frequent as the clock, but much less frequent than the blinker, toad, beacon or pulsar. It is the only known oscillator that is a polyomino in more than one phase (besides the blinker).
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In the news
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- April 8: David Bell constructs and refines a puffer demonstrating that all sufficiently high c/4 diagonal rake periods are achievable. Matthias Merzenich uses this to construct a clean p3532+4N rake.
- March 31: Entity Valkyrie builds a complete 2c/3-wire-based pseudo-Heisenburp device with 742-tick repeat time.
- March 27-30: Entity Valkyrie completes a 2c/3 receiver with a repeat time of 876 ticks, which Adam P. Goucher eventually improves to 742 ticks using staged recovery mechanisms; the previous record-setting receivers needed 964 or 970 ticks to recover.
- March 20: Period1GliderGun discovers a period-26 bouncer-based reflector, the first independent reflector of this period, using components by Nico Brown and Dean Hickerson.
- March 19: Keith Amling constructs new p6 c/2 orthogonal greystretchers in which the stripes are bounded by extended tables.
- March 18: Nathaniel Johnston posts a YouTube video about the discovery of the true period-15 glider gun and period-16 glider gun, and the history leading up to those discoveries.
- March 17: James Pascua discovers the first period-16 90-degree independent reflector based on a suggestion by Matthias Merzenich, using the period-16 glider gun to hassle a honey farm predecessor and produce a banana spark. 90-degree reflectors are known for all periods except 14, 17, and 19 with periods 15, 23, and 26 having only dependent reflectors.
- March 16-17: Keith Amling completes a new c/4 diagonal unstable puffer engine (only the third known puffer engine at this speed) based on a partial result by Matthias Merzenich. Caleb R. Hilton uses sparkers to stabilise the unstable engine into explicit puffers. David Bell uses this engine to construct the first p52 c/4 diagonal rake, and "b3s23love" and Merzenich use it to substantially reduce the size of the p108 c/4 diagonal rake.
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Did you know...
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- ... that there are at least four known ways to send information diagonally at a speed greater than the maximum spaceship speed through vacuum? (Complete mechanisms include speeds approaching c/2 via two perpendicular telegraphs, and 2c/3 via a 2c/3 wire.)
- ... that an oscillator with strict volatility 1 can be constructed for any period 945 or higher?
- ... that the original Gemini's "below-the-elbow" construction efficiency, roughly three gliders per still life, is about four times better than that of any subsequent self-constructing spaceship?
- ... 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 2022, no finite elementary replicators have been found in Life?
- ... that while multiple c/12 diagonal spaceships are known, all of them actually travel at some multiple of 8c/96 diagonal - no pure c/12 diagonal technology is known?
- ... 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?
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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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