Difference between revisions of "Crab"

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{{Spaceship|name=Crab|pname=crab|dir=Diagonal|p=4|s=c/4|bx=13|by=12|c=25|discoverer=Jason Summers|discoveryear=2000|life105=true|life106=true|plaintext=true|rle=true|animated=true}}
{{Spaceship
'''Crab''' is the smallest known diagonal [[spaceship]] other than the [[glider]]. It consists of two gliders pulling a [[tagalong]].
|name             = Crab
|pname           = crab
|type            = Tagalong
|c                = 25
|bx              = 13
|by              = 12
|dir             = Diagonal
|p               = 4
|m                = 2
|s               = c/4
|z                = c/4
|h                = 22.0
|discoverer       = Jason Summers
|discoveryear     = 2000
|rulemin          = B3/S23
|rulemax          = B3678/S23678
|rulespecial      = [[Conway's Game of Life|Conway Life]]
|isorulemin      = B3-cey/S2-in3ajnqr
|isorulemax      = B2i34-ajkr5-knq678/S234-akrw5-jq678
|synthesis        = 14
|synthesisRLE    = true
|plaintext       = true
|rle             = true
|animated         = true
|viewerconfig    = #C [[ TRACKLOOP 4 -1/4 -1/4 THUMBSIZE 2 GPS 4 ]]
|apgcode          = xq4_go217z1b6koox84szy323
|pentadecathlonid = 25P4H1V1.1
}}
'''Crab''' (or '''quarter'''<ref>{{CiteLexicon|lex_q.htm#quarter|name=quarter}}</ref>) is a [[c/4 diagonal]] [[spaceship]] that was found by [[Jason Summers]] in September {{year|2000}}. It is the smallest known diagonal spaceship other than the [[glider]] and it consists of two gliders pulling a [[tagalong]].


Crab was discovered by [[:Category:Patterns found by Jason Summers|Jason Summers]] in September [[:Category:Patterns found in 2000|2000]].
It was noticed by [[Nicolay Beluchenko]] in August {{year|2005}} that it can be converted into a small [[tubstretcher]], as shown below.<ref>{{cite web|url=http://pentadecathlon.com/lifeNews/2005/08/new_c4_diagonal_tubstretcher_1.html|title=New c/4 Diagonal Tubstretcher|publisher=Game of Life News|author=H. Koenig|accessdate=May 9, 2009|date=August 5, 2005}}</ref> This tubstretcher is the basis for the [[one per generation]] pattern.
 
Due to the diagonal glide symmetry and by simple inspection, the spaceship can easily be made to stretch two tub wicks simultaneously, via a [[domino]] [[spark]] repeatedly adding units to a tub or long^N [[barge]]. Additional non-stretching variants are possible by adding [[tubeater|tub-eating]] c/4 spaceships at the back of the chain(s), at any distance. Such a double wickstretcher was used as the basis for the [[Speed Demonoid]].
 
[[Martin Grant]] found a synthesis for crab with the help of Tanner Jacobi and Brett Berger on December 26, {{year|2014}}.<ref>{{cite web|url=http://conwaylife.com/forums/viewtopic.php?f=2&t=1533#p15243|title=Re: How about a crab synthesis?|author=Martin Grant|date=December 26, 2014 |accessdate=December 26, 2014}}</ref> The cost has since been reduced several times, most recently to 14 gliders by [[Tanner Jacobi]] on August 16, {{year|2020}}.<ref>{{cite web|url=https://www.conwaylife.com/forums/viewtopic.php?p=102367#p102367|title=Re: One Glider Seeds|author=Tanner Jacobi|date=August 16, 2020 |accessdate=August 16, 2020}}</ref>
 
==Image gallery==
{|
|-
|[[Image:crab_tubstretcher.png|framed|left|The crab as a tubstretcher.<br />{{JavaRLE|crabtubstretcher|brief}}]]
|}


==See also==
==See also==
*[[Canada goose]]
*[[Canada goose]]
*[[Orion]]
*[[Orion]]
*[[27P4H1V1]]
==References==
<references />
== External links ==
{{LinkLexicon|lex_q.htm#quarter|name=Quarter}}
{{LinkPentadecathlonObject|25P4H1V1.1}}
{{LinkCatagolue|xq4_go217z1b6koox84szy323}}
[[Category:Glide symmetric spaceships]]
[[Category:Glide symmetric spaceships]]

Revision as of 01:41, 12 December 2020

Crab
8b2o3b$7b2o4b$9bo3b$11b2o$10bo2b2$9bo2bo$b2o5b2o3b$2o5bo5b$2bo4bobo3b$ 4b2o2bo4b$4b2o! #C [[ THUMBSIZE 2 THEME 6 GRID GRIDMAJOR 0 SUPPRESS THUMBLAUNCH ]] #C [[ AUTOSTART ]] #C [[ TRACKLOOP 4 -1/4 -1/4 THUMBSIZE 2 GPS 4 ]]
Pattern type Tagalong
Spaceship
Number of cells 25
Bounding box 13 × 12
Direction Diagonal
Period 4
Mod 2
Speed c/4 | c/4
Heat 22.0
Discovered by Jason Summers
Year of discovery 2000

Crab (or quarter[1]) is a c/4 diagonal spaceship that was found by Jason Summers in September 2000. It is the smallest known diagonal spaceship other than the glider and it consists of two gliders pulling a tagalong.

It was noticed by Nicolay Beluchenko in August 2005 that it can be converted into a small tubstretcher, as shown below.[2] This tubstretcher is the basis for the one per generation pattern.

Due to the diagonal glide symmetry and by simple inspection, the spaceship can easily be made to stretch two tub wicks simultaneously, via a domino spark repeatedly adding units to a tub or long^N barge. Additional non-stretching variants are possible by adding tub-eating c/4 spaceships at the back of the chain(s), at any distance. Such a double wickstretcher was used as the basis for the Speed Demonoid.

Martin Grant found a synthesis for crab with the help of Tanner Jacobi and Brett Berger on December 26, 2014.[3] The cost has since been reduced several times, most recently to 14 gliders by Tanner Jacobi on August 16, 2020.[4]

Image gallery

The crab as a tubstretcher.
RLE: here

See also

References

  1. "quarter". The Life Lexicon. Stephen Silver.
  2. H. Koenig (August 5, 2005). "New c/4 Diagonal Tubstretcher". Game of Life News. Retrieved on May 9, 2009.
  3. Martin Grant (December 26, 2014). "Re: How about a crab synthesis?". Retrieved on December 26, 2014.
  4. Tanner Jacobi (August 16, 2020). "Re: One Glider Seeds". Retrieved on August 16, 2020.

External links