R2-D2
| R2-D2 | |||||||||
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| Pattern type | Oscillator | ||||||||
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| Oscillator type | Billiard table | ||||||||
| Number of cells | 29 | ||||||||
| Bounding box | 11 × 10 | ||||||||
| Period | 8 (mod: 4) | ||||||||
| Heat | 2.0 | ||||||||
| Volatility | 0.22 | 0.22 | ||||||||
| Kinetic symmetry | -c+e | ||||||||
| Discovered by | Peter Raynham | ||||||||
| Year of discovery | Unknown | ||||||||
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R2-D2 is a period-8 oscillator that was found in the form shown in the infobox at right, but not named, by Peter Raynham in the early 1970s. The name derives from a form with a larger and less symmetric stator discovered later by Noam Elkies in August 1994, shown below.[1]
| R2-D2 stator from 1994 (which inspired the name) (click above to open LifeViewer) RLE: here Plaintext: here Catagolue: here |
Goldtiger997 found a 86-glider synthesis for this oscillator on March 7, 2020.[2] On September 22, 2025, vilc, ElijahKen, and KtT reduced the cost to 25 gliders.[3][4]
On 2022-11-30, the shown variant with the smallest stator appeared in a symmetric soup discovered by the Open Science Grid, albeit not in a way useful to synthesis, with the initial soup matching 50 states of the 70 cells in its minimal covering octagon and the mechanism forming entirely in one generation, with pre-blocks becoming blocks in the next.[5]
A p5 diamond and four copies of R2-D2 can mutually rephase each other to create a p17 oscillator.
| A period-17 oscillator that phase shifts the p5 diamond using R2-D2 (click above to open LifeViewer) RLE: here Plaintext: here Catagolue: here |
See also
References
- ↑ Dean Hickerson's oscillator stamp collection. Retrieved on March 14, 2020.
- ↑ Goldtiger997 (March 7, 2020). Re: Synthesising Oscillators (discussion thread) at the ConwayLife.com forums
- ↑ KtT (September 22, 2025). Re: Synthesising Oscillators (discussion thread) at the ConwayLife.com forums
- ↑ shinjuku (#11449190585) (September 22, 2025). Job triggered by Adam P. Goucher at GitLab Catagolue project.
- ↑ the attribute page, the soup
External links
- R2-D2 at the Life Lexicon
- R2-D2 at Adam P. Goucher's Catagolue
- 29P8.2 at Heinrich Koenig's Game of Life Object Catalogs
- R2-D2 at Wikipedia (name origin)
- Patterns
- Oscillators with 29 cells
- Periodic objects with minimum population 29
- Patterns with 29 cells
- Patterns found by Peter Raynham
- Patterns that can be constructed with 25 gliders
- Oscillators
- Billiard tables
- Oscillators with period 8
- Oscillators with mod 4
- Oscillators with heat 2
- Oscillators with volatility 0.22
- Oscillators with strict volatility 0.22
- Oscillators with -c+e symmetry