# LifeWiki:Did you know

From LifeWiki

This page is for organizing the "did you know..." box that appears on the LifeWiki main page.

## Instructions

- Add new items at the first red link in the section below.
- Update the main page (or ask an administrator to update the main page) so that {{LifeWiki:Did you know|total=12|show=9}} has the "total" parameter equal to the number of non-empty subpages. The "show" parameter must not be more than 20.

If you have any difficulty, problems or questions relating to the technical side of this sub-page, ask at the LifeWiki:Did you know talk page.

### Current DYKs

Did you know...

- LifeWiki:Did you know/1: ... that the longest interesting pattern constructed, the caterpillar, contains over 11 million cells, and the 0E0P metacell contains over 18 million cells?
- LifeWiki:Did you know/2: ... that the Gosper glider gun was the first pattern to be discovered that exhibits infinite growth?
- LifeWiki:Did you know/3: ... that the block-laying switch engine and the glider-producing switch engine (and various combinations of two switch engines) are the only infinitely-growing patterns that are known to have ever occurred naturally from an asymmetric random starting configuration?
- LifeWiki:Did you know/4: ... that oscillators are known that oscillate at all periods other than 19, 23, 34, 38 and 41?
- LifeWiki:Did you know/5: ... that the pentadecathlon and the blinker are the only known oscillators that are polyominos in more than one phase?
- LifeWiki:Did you know/6: ... that it is impossible for a period 3 oscillator to be a phoenix?
- LifeWiki:Did you know/7: ... that the 16×16 soup with the longest known lifespan lasts for over 47,000 generations before stabilizing?
- LifeWiki:Did you know/8: ... that replicators with quadratic population growth have been known to exist in Conway's Game of Life since the early 1970s, but none were found until 2018 when Adam P. Goucher constructed the 0E0P metacell?
- LifeWiki:Did you know/9: ... that the first known period 37 and 51 oscillators were found in 2009?
- LifeWiki:Did you know/10: ... that a pattern whose population grows without bound but does not tend to infinity is known as a sawtooth?
- LifeWiki:Did you know/11: ... that there are over 6.5 million distinct strict still lifes with 24 or fewer cells?
- LifeWiki:Did you know/12: ... that some infinitely-growing patterns can be constructed with as few as three gliders?
- LifeWiki:Did you know/13: ... that quadratically-growing patterns have been found with as few as 23 initial cells?
- LifeWiki:Did you know/14: ... that the blinker is the only known oscillator that is one cell thick?
- LifeWiki:Did you know/15: ... that the first spaceship found in Conway's Game of Life that travels in an oblique direction was discovered in 2010?
- LifeWiki:Did you know/16: ... that there are still lifes (such as the quad pseudo still life) that can be split into four stable islands, but not two or three?
- LifeWiki:Did you know/17: ... that no new spaceship speeds were discovered after 1970 until 1989?
- LifeWiki:Did you know/18: ... that the first stable reflector was found in October 1996, and the first fast stable reflector appeared in 2013, allowing the construction of oscillators of all periods ≥43 ticks?
- LifeWiki:Did you know/19: ... that nineteen spaceship velocities have been constructed, excluding several infinitely adjustable families of ships?
- LifeWiki:Did you know/20: ... that there are 71 distinct ways for two gliders to collide, but it is unknown how many distinct 3-glider collisions there are?
- LifeWiki:Did you know/21: ... that to display the smallest known gun pattern for a Gemini spaceship at 1 cell = 1 pixel, on a standard-density video monitor, a screen over one mile square would be needed?
- LifeWiki:Did you know/22: ... that no odd-period glider guns were known before 1995, when a period 565 p5-spark-assisted B-heptomino loop was constructed by David Buckingham?
- LifeWiki:Did you know/23: ... that even though the speed limit for spaceships is c/2 in a vacuum, in a medium of stripes agar there are "spaceships" that can travel at lightspeed along the stripes, or two thirds of lightspeed perpendicular to the stripes?
- LifeWiki:Did you know/24: ... that the smallest known spacefiller pattern consists of 187 cells?
- LifeWiki:Did you know/25: ... that the smallest known sawtooth pattern in Conway's Life consists of only 177 cells?
- LifeWiki:Did you know/26: ... that there are now over a hundred and twenty known Herschel conduits, counting stable conduits only, and a much larger number if oscillator-supported conduits are included?
- LifeWiki:Did you know/27: ... that Demonoids, Caterloopillars, Orthogonoids, half-bakery knightships are the only known types of spaceships with fixed slope but adjustable speed -- not counting 0E0P metacell-based patterns?
- LifeWiki:Did you know/28: ... that a pattern exists in which no cell in the unbounded Life plane ever becomes periodic?
- LifeWiki:Did you know/29: ... 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?
- LifeWiki:Did you know/30: ... that there are dozens of known Cordership variants, including puffers, rakes and wickstretchers, with periods of any multiple of 96?
- LifeWiki:Did you know/31: ... that greyships have been constructed with speeds of c/2, c/3, c/4, c/5, and 2c/5?
- LifeWiki:Did you know/32: ... that most greyships travel parallel to the stripes in their included agars, but a few travel perpendicular to the stripes, or "against the grain"?
- LifeWiki:Did you know/33: ... 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?
- LifeWiki:Did you know/34: ... that several different patterns have been constructed to calculate and display the sequence of prime numbers, and some have been adapted to display only twin primes or Fermat primes?
- LifeWiki:Did you know/35: ... that two completely different types of oblique spaceships, the waterbear and the half-baked knightship, were constructed in 2014?
- LifeWiki:Did you know/36: ... that no Caterpillar-type spaceships were completed for almost ten years after the original Caterpillar was constructed in 2004, but that two different designs, the waterbear and the centipede, were finished in 2014?
- LifeWiki:Did you know/37: ... that the first spiral-growth pattern in Conway's Life was constructed in 2014?
- LifeWiki:Did you know/38: ... that among known glider recipes for irreducible objects, the Gemini spaceship has the largest known minimal recipe, currently 173,449 gliders — the runner-up being the Parallel HBK with a 38,380-glider synthesis?
- LifeWiki:Did you know/39: ... that it was shown in 2014 that any salvo of gliders, no matter how tightly packed, can be constructed by crashing together gliders whose initial positions are farther apart than any chosen finite distance?
- LifeWiki:Did you know/40: ... that no spaceships with velocities other than c/4 diagonal (glider), c/2 orthogonal (*WSS variants), and c/12 diagonal (Corderships) had known glider syntheses until 2003, when a 2c/5 spaceship gun was constructed?
- LifeWiki:Did you know/41: ... that after ten years with no new small spaceship syntheses, a glider construction was found for the c/7 loafer in 2013?
- LifeWiki:Did you know/42: ... that glider constructions for three previously inconstructible spaceships (the dart, the crab, and the Parallel HBK) were discovered in 2014?
- LifeWiki:Did you know/43: ... that glider constructions for the B29, X66, half-X66 with HWSS, Pushalong 1, 25P3H1V0.1, 30P5H2V0, 30P4H2V0.4, a pufferfish spaceship, and the weekender were discovered in 2015 — after fifteen years of intermittent efforts in the case of the weekender?
- LifeWiki:Did you know/44: ... that since 2014, more new spaceship syntheses have been completed than were found in all the years between 1970 and 2013?
- LifeWiki:Did you know/45: ... that as of 17 July 2019 there are 224 different still lifes known to be constructible by colliding four gliders, but it is likely that this list is not complete?
- LifeWiki:Did you know/46: ... that in 2014 a new natural infinite growth pattern was discovered, starting from a symmetric random starting configuration?
- LifeWiki:Did you know/47: ... that the first self-constructing Conway's Life pattern was built in 2010?
- LifeWiki:Did you know/48: ... that the first glider synthesis for a c/3 spaceship was completed in 2014?
- LifeWiki:Did you know/49: ... that the first "macro-spaceship" gun (a Gemini spaceship gun) was constructed in 2010, followed by the HBK gun in January 2015 and a Demonoid gun in December 2015?
- LifeWiki:Did you know/50: ... that the waterbear was the first known high-speed oblique spaceship, many orders of magnitude faster than Gemini spaceships and half-baked knightships?
- LifeWiki:Did you know/51: ... that there are no known direct reflectors for lightspeed wire signals, or for signals in 2c/3 wires, but that very large reflectors for these signals can be constructed using stable or periodic circuitry?
- LifeWiki:Did you know/52: ... that 24 ten-cell patterns exhibit infinite growth, with 17 unique pattern types, but that it has been proven that no nine-cell pattern exhibits infinite growth?
- LifeWiki:Did you know/53: ... that all still lifes up to 18 bits have a known glider synthesis, but it is still not known whether all still lifes are synthesizable?
- LifeWiki:Did you know/54: ... that the French kiss remained without a glider synthesis until 2013?
- LifeWiki:Did you know/55: ... that Adam P. Goucher's distributed Catagolue soup-search project, started in February 2015, has already tested more random soups than any previous such project, and has contributed to the reduction of many glider construction recipes?
- LifeWiki:Did you know/56: ... that with the appearance of the 0E0P metacell, the number of periods for which strict volatility 1 oscillators were known went from 12 to infinity?
- LifeWiki:Did you know/57: ... that Copperhead is not only the first c/10 orthogonal spaceship ever found, but also remarkably compact for a pattern not discovered until 2016?
- LifeWiki:Did you know/58: ... that loafer is the fifth smallest non-flotilla spaceship, but was discovered 43 years after the four spaceships smaller than it?
- LifeWiki:Did you know/59: ... that despite being the fourth smallest non-flotilla orthogonal spaceship, loafer has never appeared from a single randomly generated soup?
- LifeWiki:Did you know/60: ... that all known glider eaters take at least four ticks to recover to their original state after eating a glider?
- LifeWiki:Did you know/61: ... that the smallest 31c/240 spaceship does not make use of the 31c/240 reaction?
- LifeWiki:Did you know/62: ... that there is roughly one chance in 10^(N/3) that a still life appearing out of random soup will have a population of exactly N cells?
- LifeWiki:Did you know/63: ... that the number of still lifes with N+1 bits is roughly 2.48 times larger than the number of N-bit still lifes?
- LifeWiki:Did you know/64: ... that the odds of a randomly-chosen 20×20 soup pattern being a methuselah that lasts between 1000N and 1000(N+1) ticks, is roughly the same as the odds that it will last
**any**amount of time longer than 1000(N+1) ticks? - LifeWiki:Did you know/65: ... that all still lifes up to 16 cells can be synthesized at a cost of less than one glider per cell?
- LifeWiki:Did you know/66: ... that the first elementary knightship, Sir Robin, was discovered only in 2018, with there having been a very close call in 2004?
- LifeWiki:Did you know/67: ... that there is a 5×2 counterexample to the Coolout Conjecture, proving that patterns that are internally compatible with stability can not always be made part of a larger still life, no matter what cells are added around the edges?
- LifeWiki:Did you know/68: ... that a Conway's Life pattern representing a complete programmable 8-bit computer, consisting only of buckaroos, p60 glider guns, and glider duplicators, was completed in November 2016?
- LifeWiki:Did you know/69: ... that whilst no elementary oblique spaceships were found in B3/S23 until 2018, and none have occurred naturally, at least two naturally occurring reactions have been discovered in B38/S23 that travel in an oblique direction?
- LifeWiki:Did you know/70: ... that not all 1.00 volatility oscillators are phoenixes, but volatility 1.00 period 2 oscillators
*must*be phoenixes? - LifeWiki:Did you know/71: ... that no pattern inside a 6×6 bounding box is a Garden of Eden?
- LifeWiki:Did you know/72: ... that Garden of Eden patterns with only 45 ON cells have been found?
- LifeWiki:Did you know/73: ... that it is known that no Garden of Eden patterns exist that are 1, 2, or 3 cells high, but that it is currently an open question whether a 4-cell-high GoE can be constructed?
- LifeWiki:Did you know/74: ... that 6-cell-high Garden of Eden patterns were constructed as far back as 1973, but 5-cell-high GoEs were unknown until Steven Eker found some in 2016?
- LifeWiki:Did you know/75: ... that in 2016, patterns were found that have great-great-grandparents but no great-great-great-grandparents?
- LifeWiki:Did you know/76: ... that no way is known for a 3×3 pattern to be tiled into an M×N rectangle to produce a Garden of Eden, but that there are 4×3, 4×4 and larger tiles that can be repeated in this way to produce GoEs?
- LifeWiki:Did you know/77: ... that there are spaceship stabilizations of agars?
- LifeWiki:Did you know/78: ... that block is the only known finite strict still life where each living cell has exactly 3 neighbours?
- LifeWiki:Did you know/79: ... that all strict still lifes up to and including 14 cells have been found by apgsearch in asymmetrical 16×16 soups?
- LifeWiki:Did you know/80: ... that c/2 orthogonal and c/4 diagonal are the only speeds of spaceships seen to emerge from asymmetric soups on Catagolue?
- LifeWiki:Did you know/81: ... that all currently known standard Herschel conduits produce the same Herschel great-grandfather pattern, except for Fx158?
- LifeWiki:Did you know/82: ... that eater 1 is the smallest asymmetric still life?
- LifeWiki:Did you know/83: ... that in Life, no spaceship can exist with a speed of (m,n)c/x where (m+n)/x > 0.5?
- LifeWiki:Did you know/84: ... that even without using fixed-cost reverse caber tosser technology, an N-bit strict still life – specifically, some length of long long (...) boat or barge – can be constructed for any odd integer N using no more than 39 gliders, and for any even integer N using no more than 38 gliders, using a temporary tubstretcher?
- LifeWiki:Did you know/85: ... that even without using fixed-cost reverse caber tosser technology, an N-bit period-2 oscillator can be constructed for any odd integer N using no more than 45 gliders, and for any even integer N using no more than 46 gliders, using a temporary tubstretcher?
- LifeWiki:Did you know/86: ... that it is currently an open question as to if there exists a periodic pattern whose only predecessors are its own evolutionary sequence?
- LifeWiki:Did you know/87: ... 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?
- LifeWiki:Did you know/88: ... that there are currently known elementary spaceships with speeds c/7 and c/10 orthogonal, but none with c/8 or c/9?
- LifeWiki:Did you know/89: ... that there are currently known elementary spaceships with speeds c/7 and c/12 diagonal, but none with c/8, c/9, c/10 or c/11?
- LifeWiki:Did you know/90: ... that while the speed limit for orthogonal spaceships in rules using the Moore neighbourhood is c orthogonal, spaceships in Larger than Life rules are capable of breaking this barrier?
- LifeWiki:Did you know/91: ... that without the use of adjustable glider loops, there are no known oscillators with periods 43 or 53?
- LifeWiki:Did you know/92: ... that without the use of Herschel loops or adjustable glider loops, there are no known oscillators with periods 59 or 61?
- LifeWiki:Did you know/93: ... that small stable elementary period multipliers (also known as pulse dividers) have been found for multipliers of 2x, 3x, and 4x, but not for 5x or higher?
- LifeWiki:Did you know/94: ... that with reverse caber-tosser universal constructor technology, it is possible to build any possible glider-constructible pattern, no matter what size, using only 35 gliders?
- LifeWiki:Did you know/95: ... 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.)
- LifeWiki:Did you know/96: ... that an oscillator with strict volatility 1 can be constructed for any period 3506909 or higher?
- LifeWiki:Did you know/97: ... 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? - LifeWiki:Did you know/98: ... 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?
- LifeWiki:Did you know/99: ... 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?
- LifeWiki:Did you know/100: ... 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?