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{{Glossary}}
{{Glossary}}
[[Image:Gosperglidergun.gif|framed|right|The first known gun, the [[Gosper glider gun]]]]
[[Image:Gosperglidergun.gif|framed|right|The first known gun, the [[Gosper glider gun]]]]
A '''gun''' is a stationary pattern that emits [[spaceship]]s (or [[rake]]s) repeatedly forever. By far the most common type of guns are '''glider guns''', which emit [[glider]]s (the most well-known of which is the [[Gosper glider gun]]); however, guns that emit spaceships of other speeds, including [[c/2 orthogonal]], [[2c/5 orthogonal]], and [[c/12 diagonal]], have also been created.
A '''gun''' is a stationary pattern that repeatedly emits [[spaceship]]s (or [[rake]]s) forever. By far the most common type of guns are '''[[glider gun]]s''', which emit [[glider]]s (the most well-known of which is the [[Gosper glider gun]]); however, guns that emit spaceships of many other speeds, including [[c/2 orthogonal]], [[2c/5 orthogonal]], and [[c/12 diagonal]], have also been created.


==History==
==History==
The first gun to be discovered, the [[Gosper glider gun]], was found by [[Bill Gosper]] in [[:Category:patterns found in 1970|1970]], being the first known pattern in [[Conway's Game of Life]] to exhibit [[infinite growth]]. Since then, many guns have been constructed with various periods and that fire spaceships of various speeds. Due to simple [[glider synthesis|glider syntheses]] of the [[Types_of_spaceships#Standard_spaceship|standard spaceships]] many c/2 spaceship guns are known. The first gun that did not fire gliders or c/2 spaceships was a '''Cordergun''' (a gun that fires [[Cordership]]s) constructed by [[Jason Summers]] in July, [[:Category:patterns found in 1999|1999]]<ref>{{cite web|url=http://entropymine.com/jason/life/status.html |title=Game of Life Status page |accessdate=October 15, 2010}}</ref> based on a synthesis of a variation of the [[7-engine Cordership]] by [[Stephen Silver]].  In March, [[:Category:patterns found in 2003|2003]] [[Noam Elkies]] completed the synthesis of [[60P5H2V0]] which [[Dave Greene]] used to construct the [[P416_60P5H2V0_gun|first 2c/5 spaceship gun]] in April of the same year.
The first gun to be discovered, the [[Gosper glider gun]], was found by [[Bill Gosper]] in {{year|1970}}, being the first known pattern in [[Conway's Game of Life]] to exhibit [[infinite growth]]. Since then, many guns have been constructed with various periods and that fire spaceships of various speeds. Due to simple [[glider synthesis|glider syntheses]] of the [[Types_of_spaceships#Standard_spaceship|standard spaceships]] many c/2 spaceship guns are known. The first gun that did not fire gliders or c/2 spaceships was a '''Cordergun''' (a gun that fires [[Cordership]]s) constructed by [[Jason Summers]] in July, {{year|1999}}<ref name="entropymine_status" /> based on a synthesis of a variation of the [[7-engine Cordership]] by [[Stephen Silver]].  In March, {{year|2003}} [[Noam Elkies]] completed the synthesis of [[60P5H2V0]] which [[Dave Greene]] used to construct the [[P416_60P5H2V0_gun|first 2c/5 spaceship gun]] in April of the same year.


In July, [[:Category:patterns found in 2010|2010]] Dave Greene constructed a few guns for a [[gemini|geminoid]] spaceship.<ref>{{Cite web|url=http://pentadecathlon.com/lifeNews/2010/07/gemini_guns_1.html|title=Gemini guns|author=Adam P. Goucher|date=July 30, 2010|accessdate=October 15, 2010}}</ref> These are the first guns that shoot obliquely-traveling spaceships and are, in terms of their bounding boxes, the largest patterns constructed in Life.
In July, {{year|2010}} Dave Greene constructed a few guns for a [[gemini|geminoid]] spaceship.<ref name="golnews201007" /> These are the first guns that shoot obliquely-traveling spaceships and at that time were the largest patterns constructed in Life, in terms of their bounding boxes.


On February 17, [[:Category:patterns found in 2013|2013]] [[Josh Ball]] discovered a simple [[c/7 orthogonal]] spaceship, [[loafer]].  Adam P. Goucher found a synthesis for loafer later that day, allowing the construction of c/7 orthogonal spaceship guns.
On February 17, {{year|2013}} [[Josh Ball]] discovered a simple [[c/7 orthogonal]] spaceship, [[loafer]].  Adam P. Goucher found a synthesis for the loafer later that day, allowing the construction of c/7 orthogonal spaceship guns.<ref name="post7466" />
 
During March {{year|2016}} the [[copperhead]] spaceship was discovered, with a glider synthesis and several guns following suit.<ref name="post28101" />
 
In {{year|2019}} and {{year|2020}} guns were produced for the spaceships [[46P4H1V0]],<ref name="post84423" /> [[spider]],<ref name="post88186" /> and [[58P5H1V1]],<ref name="post97489" /> of speeds [[c/4 orthogonal]], [[c/5 orthogonal]], and [[c/5 diagonal]] respectively.


==Barrels==
==Barrels==
It is not uncommon for glider guns to have multiple '''barrels'''; that is, streams of gliders that come out along multiple different paths. For example, the [[B-52 bomber]] is said to be double-barreled because it produces two streams of gliders (one toward the northwest and another toward the southeast). [[Gunstar]] and its variants all have four barrels, and [[P94S]] contains a whopping 12 barrels. Given a gun with multiple barrels, one can eliminate barrels by simply placing an [[eater 1]] in the path of the unwanted glider streams.
{{main|Barrel}}
The barrel of a gun (or rake) is a path along which spaceships travel. For example, a double-barrelled glider gun is a gun that emits two glider streams.


==Pseudo-period guns==
==Pseudo-period guns==
A '''pseudo-[[period]] gun''' (as opposed to a [[#True-period guns|true-period gun]]) is a gun that emits a period n stream of spaceships (or rakes) via a mechanism that oscillates with a period different from n -- this period will necessarily be a multiple of n. Pseudo period n glider guns are known to exist for all periods greater than or equal to 14, with smaller periods being impossible. The first pseudo period 14 gun was built by [[Dietrich Leithner]] in [[:Category:Patterns found in 1995|1995]].
A '''pseudo-[[period]] gun''' (as opposed to a [[true-period]] gun) is a gun that emits a period n stream of spaceships (or rakes) via a mechanism that oscillates with a period different from n -- this period will necessarily be a multiple of n. Pseudo period n glider guns are known to exist for all periods greater than or equal to 14, with smaller periods being impossible. The first pseudo period 14 gun was built by [[Dietrich Leithner]] in {{year|1995}}.


==True-period guns==
==True-period guns==
A '''true-period gun''' (as opposed to a [[#Pseudo-period guns|pseudo-period gun]]) is a gun that emits a period n stream of spaceships (or rakes) via a mechanism that oscillates with period equal to n. True period n guns are known to exist for all periods greater than 61<ref>{{Cite web|url=http://www.radicaleye.com/lifepage/patterns/bhept/bhept.html|title=My Experience with B-heptominos in Oscillators|author=Dave Buckingham|accessdate=May 14, 2009|date=October 12, 1996)}}</ref>, but only a few smaller periods have been achieved, namely  20, [[True_period_22_gun|22]], [[True_period_24_gun|24]], [[Gosper_glider_gun|30]], [[Period-36_Glider_Gun|36]], 40, [[P44_pi-heptomino_hassler|44]], [[Period-45_glider_gun|45]], [[New gun 1|46]], 48, 50, 54, 55, 56, [[Period-59_glider_gun|59]] and [[Period-60_glider_gun|60]]. Credits for these small period guns are as follows: p30, p46 and p60 by [[Bill Gosper]] in [[:Category:patterns found in 1970|1970]]-[[:Category:patterns found in 1971|1971]], p44 by [[David Buckingham]] in [[:Category:patterns found in 1992|1992]], p50 by [[Dean Hickerson]] in [[:Category:patterns found in 1996|1996]], p24 and p48 by [[Noam Elkies]] in [[:Category:patterns found in 1997|1997]], p54 and p56 by [[Dietrich Leithner]] in early [[:Category:patterns found in 1998|1998]], p55 by [[Stephen Silver]] in late 1998, p22 by [[David Eppstein]] in [[:Category:patterns found in 2000|2000]], p36 by [[Jason Summers]] in [[:Category:patterns found in 2004|2004]], p59 by [[Adam P. Goucher]] in [[:Category:patterns found in 2009|2009]], p45 by [[Matthias Merzenich]] in [[:Category:patterns found in 2010|2010]], p40 by Adam P. Goucher and Matthias Merzenich in March [[:Category:patterns found in 2013|2013]], and p20 by Matthias Merzenich and Noam Elkies in May 2013.
A '''true-period gun''' (as opposed to a [[#Pseudo-period guns|pseudo-period gun]]) is a gun that emits a period n stream of spaceships (or rakes) via a mechanism that oscillates with period equal to n. True period n guns are known to exist for all possible periods except for 17, 19, 23, 26, 29, and 31. Credits for gun periods below 62 are as follows:
 
<table border="0" cellpadding="0" cellspacing="0" width="100%"><tr>
{| class="wikitable sortable"
|-
! Period
! Discoverer
! Year of discovery
|-
! [[Period-14 glider gun|14]]
| [[Matthias Merzenich]] and [[James Pascua]]
| {{year|2025}}
|-
! [[Period-15 glider gun|15]]
| [[Period1GliderGun]] and [[Carson Cheng]]
| {{year|2024}}
|-
! [[Period-16 glider gun|16]]
| [[Period1GliderGun]] and [[Nora Brown]]
| {{year|2024}}
|-
! [[Period-18 glider gun|18]]
| [[400spartans]], Period1GliderGun, and [[David Raucci]]
| {{year|2025}}
|-
! [[Period-20 glider gun|20]]
| Matthias Merzenich and [[Noam Elkies]]
| {{year|2013}}
|-
! [[Period-21 glider gun|21]]
| [[Tanner Jacobi]] and David Raucci
| {{year|2021}}
|-
! [[Period-22 glider gun|22]]
| [[David Eppstein]] and [[Jason Summers]]
| {{year|2000}}
|-
! [[Period-24 glider gun|24]]
| Noam Elkies
| {{year|1997}}
|-
! [[period-25 glider gun|25]]
| [[Mitchell Riley]]
| {{year|2022}}
|-
! [[Period-27 glider gun|27]]
| David Raucci and [[goldenratio]]
| {{year|2022}}
|-
! [[Period-28 glider gun|28]]
| Matthias Merzenich and [[Paul Callahan]]
| {{year|2020}}
|-
! [[Gosper_glider_gun|30]]
| [[Bill Gosper]]
| {{year|1970}}
|-
! [[Period-32 glider gun|32]]
| Matthias Merzenich, David Raucci, [[praosylen]], [[Aleph]], and Noam Elkies
| {{year|2021}}
|-
! [[Period-33 glider gun|33]]
| [[Arie Paap]] and Matthias Merzenich
| {{year|2018}}
|-
! [[Period-34 glider gun|34]]
| [[Nora Brown]]
| {{year|2022}}
|-
! [[Period-35 glider gun|35]]
| Matthias Merzenich, [[iNoMed]], and [[hotcrystal0]]
| {{year|2024}}
|-
! [[Period-36 glider gun|36]]
| Jason Summers
| {{year|2004}}
|-
! [[Period-37 glider gun|37]]
| iNoMed, goldenratio, and [[Luke Kiernan]]
| {{year|2022}}
|-
! [[Period-38 glider gun|38]]
| [[Luka Okanishi]] and Period1GliderGun
| {{year|2026}}
|-
! [[Period-39 glider gun|39]]
| [[Caleb R. Hilton]] and Nora Brown
| {{year|2026}}
|-
! [[Period-40 glider gun|40]]
| [[Adam P. Goucher]], Jason Summers, and Matthias Merzenich
| {{year|2013}}
|-
! [[Period-41 glider gun|41]]
| iNoMed, Matthias Merzenich, [[May13]], David Raucci, and Nora Brown
| {{year|2023}}
|-
! [[Period-42 glider gun|42]]
| Tanner Jacobi and David Raucci
| {{year|2021}}
|-
! [[Period-43 glider gun|43]]
| Nora Brown
| {{year|2022}}
|-
! [[p44_pi-heptomino_hassler|44]]
| [[David Buckingham]]
| {{year|1992}}
|-
! [[period-45_glider_gun|45]]
| Matthias Merzenich
| {{year|2010}}
|-
! [[new_gun_1|46]]
| Bill Gosper
| {{year|1971}}
|-
! [[Period-47 glider gun|47]]
| [[Entity Valkyrie]] and iNoMed
| {{year|2024}}
|-
! [[Period-48 glider gun|48]]
| Noam Elkies
| {{year|1997}}
|-
! [[hotcrystal0_reaction#Generalized_form|49]]
| Tanner Jacobi, Aleph, and hotcrystal0
| {{year|2021}}
|-
! [[Period-50 glider gun|50]]
| [[Dean Hickerson]] and Noam Elkies
| {{year|1996}}
|-
! [[hotcrystal0_reaction#Generalized_form|51]]
| [[Luka Okanishi]], Aleph, and hotcrystal0
| {{year|2021}}
|-
! [[Period-52 glider gun|52]]
| [[Dave Greene]], [[Chris Cain]], Matthias Merzenich and Adam P. Goucher
| {{year|2018}}
|-
! [[Period-53 glider gun|53]]
| iNoMed and goldenratio
| {{year|2024}}
|-
! [[Quetzal#Quetzal-54|54]]
| [[Dietrich Leithner]]
| {{year|1998}}
|-
! [[Quetzal#Quetzal-55|55]]
| [[Stephen Silver]]
| {{year|1998}}
|-
! [[Quetzal#Quetzal-56|56]]
| Dietrich Leithner
| {{year|1998}}
|-
! [[Quetzal#Quetzal-57|57]]
| Matthias Merzenich
| {{year|2016}}
|-
! [[Quetzal#Quetzal-58|58]]
| [[Maia Karpovich]], Matthias Merzenich, and Chris Cain
| {{year|2016}}
|-
! [[period-59_glider_gun|59]]
| Adam P. Goucher and Jason Summers
| {{year|2009}}
|-
! [[period-60_glider_gun|60]]
| Bill Gosper
| {{year|1970}}
|-
! [[Period-61 glider gun|61]]
| Luka Okanishi
| {{year|2016}}
|}
 
==Smallest guns by area of bounding box==
 
A collection of smallest guns by bounding box area was originally created and maintained by [[Dietrich Leithner]] and [[Peter Rott]], before [[Jason Summers]] took over the maintenance. The p14-999 collection had subsequently evolved into a Git repository led by [[Chris Cain]]. Currently, the collection is maintained collaboratively at Catagolue's glider-synthesis database.
 
* [https://catagolue.hatsya.com/census/b3s23/synthesis-costs/gun Current database] (Catagolue)
* [https://github.com/ceebo/glider_guns/ older repository] maintained by Chris Cain (only p14-1024)
* [https://entropymine.com/jason/life/#collections older version] maintained by Jason Summers (includes some periods in the range p1000-9999).
 
Note that this classification of smallest is of dubious utility: see [[Pointless optimisation game]] for more details.


==Guns in Life-like cellular automata==
==Guns in Life-like cellular automata==
Due to the existence of some small spaceships in [[Cellular_automaton#Life-like_cellular_automata|Life-like cellular automata]] with birth at two live neighbours (B2), many low-period spaceship guns have been found using tools such as [[WinLifeSearch]]. In contrast, there are very few rules without B2 that are known to contain guns. The following is a list of rules without B2 that have known guns:
Due to the existence of some small spaceships in [[Life-like cellular automata]] with birth at two live neighbours (B2), many low-period spaceship guns have been found using tools such as [[WinLifeSearch]]. In contrast, there are very few outer-totalistic rules without B2 (and B0) that are known to contain guns. The following is a list of outer-totalistic rules with neither B0 nor B2 that have known guns:
{| style="width:100%" |
{| style="width:100%" |
|-
|-
| valign="top" width="50%" |
| valign="top" width="50%" |
* Glider guns
* Glider guns<ref name="thread1071" />
** B3/S23 ([[Conway's Game of Life]])
** B3/S23 ([[Conway's Game of Life]])
** B3/S236
** B3/S236
Line 32: Line 223:
** B3/S237
** B3/S237
** B3/S2378
** B3/S2378
** B3/S238
** B3/S238 ({{rl|EightLife}})
** B36/S23 ([[HighLife]])
** B36/S23 ({{rl|HighLife}})
** B36/S237
** B36/S237
** B36/S2378
** B36/S2378
** B36/S238
** B36/S238
** B368/S23
** B368/S23
** B368/S238
** B368/S238 ({{rl|LowDeath}})
** B37/S23 ([[DryLife]])
** B37/S23 ({{rl|DryLife}})
** B37/S236
** B37/S237
** B37/S237
** B37/S238
** B37/S238
** B37/S2378
** B378/S23
** B378/S23
** B378/S237
** B378/S237
Line 50: Line 243:
** B38/S23678
** B38/S23678
** B38/S2368
** B38/S2368
** B38/S23
** B38/S23 ({{rl|Pedestrian Life}})
** B38/S237
** B38/S237
** B38/S2378
** B38/S2378
** B38/S238
** B38/S238 ({{rl|HoneyLife}})
| valign="top" |
| valign="top" |
* Other guns
* Other guns
** B3/S23 (Conway's Game of Life)
** B3/S23 ([[Conway's Game of Life]])
** B3/S237
** B3/S237
** B3/S2378
** B3/S2378
** B3/S238
** B3/S238 ({{rl|EightLife}})
** B35/S236
** B3/S345
** {{rl|B35/S236}}
** B357/S238 ({{rl|Pseudo Life}})
** B358/S236
** B358/S236
** B36/S23 (HighLife)
** B36/S125 ({{rl|2x2}})
** B36/S23 ({{rl|HighLife}})
** B36/S237
** B36/S237
** B36/S2378
** B36/S2378
** B36/S238
** B36/S238
** B368/S23
** B368/S23
** B368/S238
** B368/S238 ({{rl|LowDeath}})
** B36/S245 ([http://www.ics.uci.edu/~eppstein/ca/replicators/b36s245.html Logarithmic replicator rule])
** B36/S245 ({{rl|sqrt replicator rule}})
** B368/S245 ([[Move]])
** B368/S245 ({{rl|Move}})
** B368/S12578
** B368/S12578
** B3678/S34678 ([[Day & Night]])
** B3678/S34678 ({{rl|Day & Night}})
** B37/S23 (DryLife)
** B37/S23 ({{rl|DryLife}})
** B37/S238
** B37/S238
** B378/S23
** B378/S23
** B378/S238
** B378/S238
** B38/S23
** B38/S23 ({{rl|Pedestrian Life}})
** B38/S237
** B38/S237
** B38/S2378
** B38/S2378
** B38/S238
** B38/S238 ({{rl|HoneyLife}})
** B38/S345
|}
|}


==See also==
==See also==
*[[:Category:Guns|List of guns]]
* {{CategoryLink|Guns}}
* [[Dieter and Peter's glider gun collection]]
* [[LifeWiki:Game_of_Life_Status_page#Glider_gun_true-periods|Glider gun true-periods status table]]
* [[LifeWiki:Game_of_Life_Status_page#Gun_pseudo-periods|Gun pseudo-periods status table]]
* [[Quetzal]]


==References==
==References==
<references />
<references>
<ref name="entropymine_status">{{cite web|url=http://entropymine.com/jason/life/status.html |title=Game of Life Status page |accessdate=October 15, 2010}}</ref>
<ref name="golnews201007">{{LinkGoLNews|2010/07/gemini_guns_1.html|title=Gemini guns|date=July 30, 2010|author=Adam P. Goucher}}</ref>
<ref name="thread1071">{{LinkForumThread|format=ref|f=11|t=1071|title=Guns in Life-like cellular automata|author=[[Matthias Merzenich]]|date=April 11, 2013}}</ref>
<ref name="post7466">{{LinkForumThread
|format = ref
|title  = Re: c/7 orthogonal spaceships
|p      = 7466
|author = Shannon Omick
|date  = February 18, 2013
}}</ref>
<ref name="post28101">{{LinkForumThread
|format = ref
|title  = Re: is this c/10 spaceship known?
|p      = 28101
|author = Alexey Nigin
|date  = March 6, 2016
}}</ref>
<ref name="post84423">{{LinkForumThread
|format = ref
|title  = Re: Stable signal converters
|p      = 84423
|author = Goldtiger997
|date  = October 22, 2019
}}</ref>
<ref name="post88186">{{LinkForumThread
|format = ref
|title  = Re: Small Spaceship Syntheses
|p      = 88186
|author = Entity Valkyrie
|date  = January 26, 2020
}}</ref>
<ref name="post97489">{{LinkForumThread
|format = ref
|title  = Re: Construction practice
|p      = 97489
|author = Entity Valkyrie
|date  = May 22, 2020
}}</ref>
</references>


==External links==
==External links==
{{LinkWeisstein|Gun.html}}
* {{LinkWikipedia|Gun_(cellular_automaton)}}
{{LinkLexicon|lex_g.htm#gun}}
* {{LinkLexicon|lex_g.htm#gun}}
* {{LinkLexicon|filename=lex_d.htm#doublebarrelled|patternname=Double-barrelled}}
* {{LinkForumThread|f=2|t=1657|title=Execution of Old Guns by Variable-Speed Firing Squad}}

Latest revision as of 00:32, 30 September 2026

The first known gun, the Gosper glider gun

A gun is a stationary pattern that repeatedly emits spaceships (or rakes) forever. By far the most common type of guns are glider guns, which emit gliders (the most well-known of which is the Gosper glider gun); however, guns that emit spaceships of many other speeds, including c/2 orthogonal, 2c/5 orthogonal, and c/12 diagonal, have also been created.

History

The first gun to be discovered, the Gosper glider gun, was found by Bill Gosper in 1970, being the first known pattern in Conway's Game of Life to exhibit infinite growth. Since then, many guns have been constructed with various periods and that fire spaceships of various speeds. Due to simple glider syntheses of the standard spaceships many c/2 spaceship guns are known. The first gun that did not fire gliders or c/2 spaceships was a Cordergun (a gun that fires Corderships) constructed by Jason Summers in July, 1999[1] based on a synthesis of a variation of the 7-engine Cordership by Stephen Silver. In March, 2003 Noam Elkies completed the synthesis of 60P5H2V0 which Dave Greene used to construct the first 2c/5 spaceship gun in April of the same year.

In July, 2010 Dave Greene constructed a few guns for a geminoid spaceship.[2] These are the first guns that shoot obliquely-traveling spaceships and at that time were the largest patterns constructed in Life, in terms of their bounding boxes.

On February 17, 2013 Josh Ball discovered a simple c/7 orthogonal spaceship, loafer. Adam P. Goucher found a synthesis for the loafer later that day, allowing the construction of c/7 orthogonal spaceship guns.[3]

During March 2016 the copperhead spaceship was discovered, with a glider synthesis and several guns following suit.[4]

In 2019 and 2020 guns were produced for the spaceships 46P4H1V0,[5] spider,[6] and 58P5H1V1,[7] of speeds c/4 orthogonal, c/5 orthogonal, and c/5 diagonal respectively.

Barrels

Main article: Barrel

The barrel of a gun (or rake) is a path along which spaceships travel. For example, a double-barrelled glider gun is a gun that emits two glider streams.

Pseudo-period guns

A pseudo-period gun (as opposed to a true-period gun) is a gun that emits a period n stream of spaceships (or rakes) via a mechanism that oscillates with a period different from n -- this period will necessarily be a multiple of n. Pseudo period n glider guns are known to exist for all periods greater than or equal to 14, with smaller periods being impossible. The first pseudo period 14 gun was built by Dietrich Leithner in 1995.

True-period guns

A true-period gun (as opposed to a pseudo-period gun) is a gun that emits a period n stream of spaceships (or rakes) via a mechanism that oscillates with period equal to n. True period n guns are known to exist for all possible periods except for 17, 19, 23, 26, 29, and 31. Credits for gun periods below 62 are as follows:

Period Discoverer Year of discovery
14 Matthias Merzenich and James Pascua 2025
15 Period1GliderGun and Carson Cheng 2024
16 Period1GliderGun and Nora Brown 2024
18 400spartans, Period1GliderGun, and David Raucci 2025
20 Matthias Merzenich and Noam Elkies 2013
21 Tanner Jacobi and David Raucci 2021
22 David Eppstein and Jason Summers 2000
24 Noam Elkies 1997
25 Mitchell Riley 2022
27 David Raucci and goldenratio 2022
28 Matthias Merzenich and Paul Callahan 2020
30 Bill Gosper 1970
32 Matthias Merzenich, David Raucci, praosylen, Aleph, and Noam Elkies 2021
33 Arie Paap and Matthias Merzenich 2018
34 Nora Brown 2022
35 Matthias Merzenich, iNoMed, and hotcrystal0 2024
36 Jason Summers 2004
37 iNoMed, goldenratio, and Luke Kiernan 2022
38 Luka Okanishi and Period1GliderGun 2026
39 Caleb R. Hilton and Nora Brown 2026
40 Adam P. Goucher, Jason Summers, and Matthias Merzenich 2013
41 iNoMed, Matthias Merzenich, May13, David Raucci, and Nora Brown 2023
42 Tanner Jacobi and David Raucci 2021
43 Nora Brown 2022
44 David Buckingham 1992
45 Matthias Merzenich 2010
46 Bill Gosper 1971
47 Entity Valkyrie and iNoMed 2024
48 Noam Elkies 1997
49 Tanner Jacobi, Aleph, and hotcrystal0 2021
50 Dean Hickerson and Noam Elkies 1996
51 Luka Okanishi, Aleph, and hotcrystal0 2021
52 Dave Greene, Chris Cain, Matthias Merzenich and Adam P. Goucher 2018
53 iNoMed and goldenratio 2024
54 Dietrich Leithner 1998
55 Stephen Silver 1998
56 Dietrich Leithner 1998
57 Matthias Merzenich 2016
58 Maia Karpovich, Matthias Merzenich, and Chris Cain 2016
59 Adam P. Goucher and Jason Summers 2009
60 Bill Gosper 1970
61 Luka Okanishi 2016

Smallest guns by area of bounding box

A collection of smallest guns by bounding box area was originally created and maintained by Dietrich Leithner and Peter Rott, before Jason Summers took over the maintenance. The p14-999 collection had subsequently evolved into a Git repository led by Chris Cain. Currently, the collection is maintained collaboratively at Catagolue's glider-synthesis database.

Note that this classification of smallest is of dubious utility: see Pointless optimisation game for more details.

Guns in Life-like cellular automata

Due to the existence of some small spaceships in Life-like cellular automata with birth at two live neighbours (B2), many low-period spaceship guns have been found using tools such as WinLifeSearch. In contrast, there are very few outer-totalistic rules without B2 (and B0) that are known to contain guns. The following is a list of outer-totalistic rules with neither B0 nor B2 that have known guns:

See also

References

  1. ↑ "Game of Life Status page". Retrieved on October 15, 2010.
  2. ↑ Gemini guns at Game of Life News. Posted by Adam P. Goucher on July 30, 2010.
  3. ↑ Shannon Omick (February 18, 2013). Re: c/7 orthogonal spaceships (discussion thread) at the ConwayLife.com forums
  4. ↑ Alexey Nigin (March 6, 2016). Re: is this c/10 spaceship known? (discussion thread) at the ConwayLife.com forums
  5. ↑ Goldtiger997 (October 22, 2019). Re: Stable signal converters (discussion thread) at the ConwayLife.com forums
  6. ↑ Entity Valkyrie (January 26, 2020). Re: Small Spaceship Syntheses (discussion thread) at the ConwayLife.com forums
  7. ↑ Entity Valkyrie (May 22, 2020). Re: Construction practice (discussion thread) at the ConwayLife.com forums
  8. ↑ Matthias Merzenich (April 11, 2013). Guns in Life-like cellular automata (discussion thread) at the ConwayLife.com forums
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