R-turner
| R-turner | |||||||||
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| Pattern type | Methuselah | ||||||||
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| Number of cells | 8 | ||||||||
| Bounding box | 5 × 4 | ||||||||
| MCPS | 8 | ||||||||
| Lifespan | 268 generations | ||||||||
| Final population | 45 | ||||||||
| L/I | 33.5 | ||||||||
| F/I | 5.6 | ||||||||
| F/L | 0.168 | ||||||||
| L/MCPS | 33.5 | ||||||||
| Static symmetry | Unspecified | ||||||||
| Discovered by | Unknown | ||||||||
| Year of discovery | Unknown | ||||||||
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The R-turner is an evolutionary sequence in Conway's Game of Life. Its name was proposed by David Raucci on July 2nd, 2021[1]. An early post on the forums by Extrementhusiast from 2009 recognized it as a methuselah with the proposed name "familiar fours", as all familiar fours appear somewhere within the evolutionary sequence[2], but this name would have caused confusion with the actual familiar fours so it was not adopted.
Commonness
On Simon Ekström's List of common evolutionary sequences, the R-turner is less common than the U-turner and H' (generation 22 of the Herschel), but is more common than the original diehard and the object hassled in Jason's p22. More specifically, it appears 28314 times on the list, with a relative frequency of 0.046.
Evolution
Initially, the R-turner moves like the Dove, spreading out in a southwest direction, leaving behind an angel at generation 44 that evolves into a blinker at generation 48. At generation 92 an R-pentomino and another angel forms, causing the "direction" of the R-turner's evolution to reverse. The R-pentomino goes on, becoming a B-heptomino while its debris is tamed by the blinker. It stabilizes at generation 268, leaving behind 3 blinkers, 5 blocks, 2 gliders, and a ship.
"R-turner without its first blinker"
"R-turner without its first blinker" refers to the following pattern, which appears at generation 64 of the R-turner's evolution:
| (click above to open LifeViewer) RLE: here Plaintext: here |
It evolves into a LoM that is quickly perturbed by a banana spark, which becomes an R-pentomino and an angel, which stabilizes at generation 204. As the name implies, most of them form via R-turners, but it can form in other ways, such as in 112P57.
In conduits
The R-turner has appeared as an intermediate in some conduits, either by itself (HB56B) or with a still life (CBx37C, CL26R). R-turner accepting conduits have also been found, though not much has been done in exploring the R-turner's use as a conduit intermediate thus far.
| an example of the R-turner as an intermediate, here with CBx37C. (click above to open LifeViewer) |
Images
See also
References
- ↑ hotdogPi (July 2, 2021). Re: Thread For Your Naming Proposals of Unnamed Patterns (discussion thread) at the ConwayLife.com forums
- ↑ Extrementhusiast (August 28, 2009). Help needed with synthesizing my methuselah (discussion thread) at the ConwayLife.com forums