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,[2] but it wasn't until the early 2020's that it started to get significant attention.
Commonness
On Simon Ekström's List of common evolutionary sequences, the R-turner appears 28314 times with a relative frequency of 0.046, making it less common than the U-turner and H' (generation 22 of the Herschel), but more common than the original diehard and the object hassled in Jason's p22.
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, ultimately stabilizing at generation 204. Although most of them form via R-turners, it can form in other ways, such as in 112P57 and in the p60 B-heptomino hassler.
In conduits
The R-turner has appeared as an intermediate in some conduits, usually with an accompanying still life that it collides with (CBx37C, CL26R, HB56B). Some R-turner accepting conduits have been found,[3] though not much has been done overall in exploring the R-turner's usefulness in conduits thus far.
| an example of the R-turner as an intermediate, here with CBx37C (click above to open LifeViewer) |
Images
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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
- ↑ Christopher D'Agostino (January 10th, 2022). Re: Random posts 2 (discussion thread) at the ConwayLife.com forums