Difference between revisions of "Gun"

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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 repeatedly emits [[spaceship]]s (or [[rake]]s) 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 {{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>{{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, {{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.
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, {{year|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 at the time were the largest patterns constructed in Life, in terms of their bounding boxes.
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, {{year|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.<ref name="post7466" />
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" />
During March {{year|2016}} the [[copperhead]] spaceship was discovered, with a glider synthesis and several guns following suit.<ref name="post28101" />
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==Barrels==
==Barrels==
The '''barrel''' of a gun (or rake) is a path along which spaceships travel. The term is most commonly used in the context of the number of barrels a gun or rake possesses, which is the number of distinct spaceship streams emitted by said gun or rake. For example, the [[AK-94]], [[B-52 bomber]] and [[Simkin glider gun]] are said to be '''double-barrelled''' because they produce two streams of gliders. The [[period-256 glider gun]] and [[Gunstar]] and its variants all have four barrels, and [[P94S]] contains 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]]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}}.
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 53<ref>{{Cite web|url=https://www.conwaylife.com/ref/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 [[Period-20 glider gun|20]], [[True period_22 gun|22]], [[True period 24 gun|24]], [[Period-28 glider gun|28]], [[Gosper glider gun|30]], [[Period-33 glider gun|33]], [[Period-36 glider gun|36]], [[Period-40 glider gun|40]], [[P44 pi-heptomino hassler|44]], [[Period-45 glider gun|45]], [[New gun 1|46]], [[True period 24 gun|48]], [[Period-50 glider gun|50]], [[Period-52 glider gun|52]]. Credits for gun periods below 62 are as follows:
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, 31, 38, and 39. Credits for gun periods below 62 are as follows:


<table border="0" cellpadding="0" cellspacing="0" width="100%"><tr>
<table border="0" cellpadding="0" cellspacing="0" width="100%"><tr>
{| class="wikitable"
{| class="wikitable sortable"
|-
|-
! Period
! Period
! Discoverer
! Discoverer
! Year of discovery
! 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]]
! [[Period-20 glider gun|20]]
| [[Matthias Merzenich]] and [[Noam Elkies]]
| Matthias Merzenich and [[Noam Elkies]]
| {{year|2013}}
| {{year|2013}}
|-
|-
! [[true_period_22_gun|22]]
! [[Period-21 glider gun|21]]
| [[Tanner Jacobi]] and David Raucci
| {{year|2021}}
|-
! [[Period-22 glider gun|22]]
| [[David Eppstein]] and [[Jason Summers]]
| [[David Eppstein]] and [[Jason Summers]]
| {{year|2000}}
| {{year|2000}}
|-
|-
! [[true_period_24_gun|24]]
! [[Period-24 glider gun|24]]
| Noam Elkies
| Noam Elkies
| {{year|1997}}
| {{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]]
! [[Period-28 glider gun|28]]
Line 49: Line 78:
| [[Bill Gosper]]
| [[Bill Gosper]]
| {{year|1970}}
| {{year|1970}}
|-
! [[Period-32 glider gun|32]]
| Matthias Merzenich, David Raucci, [[praosylen]], [[wwei23]], and Noam Elkies
| {{year|2021}}
|-
|-
! [[Period-33 glider gun|33]]
! [[Period-33 glider gun|33]]
| [[Arie Paap]] and Matthias Merzenich
| [[Arie Paap]] and Matthias Merzenich
| {{year|2018}}
| {{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]]
! [[Period-36 glider gun|36]]
| Jason Summers
| Jason Summers
| {{year|2004}}
| {{year|2004}}
|-
! [[Period-37 glider gun|37]]
| iNoMed, goldenratio, and [[Luke Kiernan]]
| {{year|2022}}
|-
|-
! [[Period-40 glider gun|40]]
! [[Period-40 glider gun|40]]
| [[Adam P. Goucher]], Jason Summers, and Matthias Merzenich
| [[Adam P. Goucher]], Jason Summers, and Matthias Merzenich
| {{year|2013}}
| {{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]]
! [[p44_pi-heptomino_hassler|44]]
Line 73: Line 130:
| Bill Gosper
| Bill Gosper
| {{year|1971}}
| {{year|1971}}
|-
! [[Period-47 glider gun|47]]
| [[Entity Valkyrie]] and iNoMed
| {{year|2024}}
|-
|-
! [[Period-48 glider gun|48]]
! [[Period-48 glider gun|48]]
| Noam Elkies
| Noam Elkies
| {{year|1997}}
| {{year|1997}}
|-
! [[hotcrystal0_reaction#Generalized_form|49]]
| Tanner Jacobi, wwei23, and hotcrystal0
| {{year|2021}}
|-
|-
! [[Period-50 glider gun|50]]
! [[Period-50 glider gun|50]]
| [[Dean Hickerson]] and Noam Elkies
| [[Dean Hickerson]] and Noam Elkies
| {{year|1996}}
| {{year|1996}}
|-
! [[hotcrystal0_reaction#Generalized_form|51]]
| [[Luka Okanishi]], wwei23, and hotcrystal0
| {{year|2021}}
|-
|-
! [[Period-52 glider gun|52]]
! [[Period-52 glider gun|52]]
| [[Dave Greene]], [[Chris Cain]], Matthias Merzenich and Adam P. Goucher
| [[Dave Greene]], [[Chris Cain]], Matthias Merzenich and Adam P. Goucher
| {{year|2018}}
| {{year|2018}}
|-
! [[Period-53 glider gun|53]]
| iNoMed and goldenratio
| {{year|2024}}
|-
|-
! [[Quetzal#Quetzal-54|54]]
! [[Quetzal#Quetzal-54|54]]
Line 103: Line 176:
|-
|-
! [[Quetzal#Quetzal-58|58]]
! [[Quetzal#Quetzal-58|58]]
| [[thunk]], Matthias Merzenich, and Chris Cain
| [[Maia Karpovich]], Matthias Merzenich, and Chris Cain
| {{year|2016}}
| {{year|2016}}
|-
|-
Line 115: Line 188:
|-
|-
! [[Period-61 glider gun|61]]
! [[Period-61 glider gun|61]]
| [[Luka Okanishi]]
| Luka Okanishi
| {{year|2016}}
| {{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==
Line 124: Line 207:
|-
|-
| valign="top" width="50%" |
| valign="top" width="50%" |
* Glider guns<ref>{{cite web|url=http://conwaylife.com/forums/viewtopic.php?f=11&t=1071|title=Guns in Life-like cellular automata|author=[[Matthias Merzenich]] (Sokwe)|date=April 11, 2013}}</ref>
* Glider guns<ref name="thread1071" />
** B3/S23 ([[Conway's Game of Life]])
** B3/S23 ([[Conway's Game of Life]])
** B3/S236
** B3/S236
Line 132: Line 215:
** B3/S237
** B3/S237
** B3/S2378
** B3/S2378
** B3/S238 ([[EightLife]])
** 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 ([[LowDeath]])
** B368/S238 ({{rl|LowDeath}})
** B37/S23 ([[DryLife]])
** B37/S23 ({{rl|DryLife}})
** B37/S236
** B37/S236
** B37/S237
** B37/S237
Line 152: Line 235:
** B38/S23678
** B38/S23678
** B38/S2368
** B38/S2368
** B38/S23 ([[Pedestrian Life]])
** B38/S23 ({{rl|Pedestrian Life}})
** B38/S237
** B38/S237
** B38/S2378
** B38/S2378
** B38/S238 ([[HoneyLife]])
** B38/S238 ({{rl|HoneyLife}})
| valign="top" |
| valign="top" |
* Other guns
* Other guns
Line 161: Line 244:
** B3/S237
** B3/S237
** B3/S2378
** B3/S2378
** B3/S238 ([[EightLife]])
** 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 ([[LowDeath]])
** 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 ([[Pedestrian Life]])
** B38/S23 ({{rl|Pedestrian Life}})
** B38/S237
** B38/S237
** B38/S2378
** B38/S2378
** B38/S238 ([[HoneyLife]])
** B38/S238 ({{rl|HoneyLife}})
** B38/S345
|}
|}


==See also==
==See also==
 
* {{CategoryLink|Guns}}
*[[Dieter and Peter's glider gun collection]]
* [[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#Glider_gun_true-periods|Glider gun true-periods status table]]
*[[LifeWiki:Game_of_Life_Status_page#Gun_pseudo-periods|Gun pseudo-periods status table]]
* [[LifeWiki:Game_of_Life_Status_page#Gun_pseudo-periods|Gun pseudo-periods status table]]
*[[:Category:Guns|List of guns]]
* [[Quetzal]]
*[[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
<ref name="post7466">{{LinkForumThread
|format     = ref
|format = ref
|title     = Re: c/7 orthogonal spaceships
|title = Re: c/7 orthogonal spaceships
|p         = 7466
|p     = 7466
|author     = Shannon Omick
|author = Shannon Omick
|date       = February 18, 2013
|date   = February 18, 2013
}}</ref>
}}</ref>
<ref name="post28101">{{LinkForumThread
<ref name="post28101">{{LinkForumThread
|format     = ref
|format = ref
|title     = Re: is this c/10 spaceship known?
|title = Re: is this c/10 spaceship known?
|p         = 28101
|p     = 28101
|author     = Alexey Nigin
|author = Alexey Nigin
|date       = March 6, 2016
|date   = March 6, 2016
}}</ref>
}}</ref>
<ref name="post84423">{{LinkForumThread
<ref name="post84423">{{LinkForumThread
Line 232: Line 321:


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

Latest revision as of 16:25, 23 March 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, 31, 38, and 39. 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, wwei23, 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
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, wwei23, and hotcrystal0 2021
50 Dean Hickerson and Noam Elkies 1996
51 Luka Okanishi, wwei23, 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

External links

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