Crab
| Crab | |||||||||
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| Pattern type | Tagalong Spaceship | ||||||||
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| Number of cells | 25 | ||||||||
| Bounding box | 13 × 12 | ||||||||
| Direction | Diagonal | ||||||||
| Period | 4 | ||||||||
| Mod | 2 | ||||||||
| Speed | c/4 | ||||||||
| Speed (unsimplified) | c/4 | ||||||||
| Heat | 22.0 | ||||||||
| Discovered by | Jason Summers | ||||||||
| Year of discovery | 2000 | ||||||||
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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.
Use as a tubstretcher
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 and the self-synthesizing oblique loopship.
| The crab as a tubstretcher (click above to open LifeViewer) RLE: here Plaintext: here |
Commonness
- Main article: List of common spaceships
At 25 cells, the crab is one of the three smallest spaceships yet to appear from soup, alongside 25P3H1V0.1 and 25P3H1V0.2.
Glider synthesis
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]
See also
- Canada goose
- Orion
- Wings
- xq4_06e4mc6332gkozog13263zw456, another spaceship pulled by two gliders with the same edge reactions (temporarily forming blocks) but that is distinct
References
- ↑ "quarter". The Life Lexicon. Stephen Silver.
- ↑ New c/4 Diagonal Tubstretcher at Game of Life News. Posted by Heinrich Koenig on August 5, 2005.
- ↑ Martin Grant (December 26, 2014). Re: How about a crab synthesis? (discussion thread) at the ConwayLife.com forums
- ↑ Tanner Jacobi (August 16, 2020). Re: One Glider Seeds (discussion thread) at the ConwayLife.com forums
External links
- Quarter at the Life Lexicon
- 25P4H1V1.1 at Heinrich Koenig's Game of Life Object Catalogs
- Crab at Adam P. Goucher's Catagolue
- Patterns
- Spaceships with 25 cells
- Periodic objects with minimum population 25
- Patterns with 25 cells
- Patterns found by Jason Summers
- Patterns found in 2000
- Patterns that can be constructed with 14 gliders
- Spaceships
- Tagalongs
- Spaceships with period 4
- Diagonal spaceships
- Spaceships with speed c/4
- Spaceships with unsimplified speed c/4
- Spaceships with heat 22
- Spaceships with mod 2
- Glide symmetric spaceships