This week's featured article
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| A spaceship (much less commonly referred to as a glider or a fish) is a finite pattern that returns to its initial state after a number of generations (known as its period) but in a different location. The speed of a spaceship is the number of cells that the pattern moves during its period. This is expressed in terms of c (the metaphorical "speed of light") which is one cell per generation; thus, a spaceship with a period of five that moves two cells to the left during its period travels at the speed of 2c/5. Most known spaceships in Life travel either orthogonally (only horizontal or vertical displacement) or diagonally (equal horizontal and vertical displacement). However, several large Conway's Life spaceships have been engineered that travel in various oblique directions, and it is known that Life has spaceships that travel in all rational directions at arbitrarily slow speeds.
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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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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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Did you know...
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- ... 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?
- ... 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?
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