Pseudo-barberpole
| Pseudo-barberpole | |||||||||
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| Pattern type | Oscillator | ||||||||
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| Family | Barberpole | ||||||||
| Number of cells | 15 | ||||||||
| Bounding box | 12 × 12 | ||||||||
| Period | 5 (mod: 5) | ||||||||
| Heat | 16.8 | ||||||||
| Volatility | 0.82 | 0.82 | ||||||||
| Kinetic symmetry | / | ||||||||
| Discovered by | Achim Flammenkamp | ||||||||
| Year of discovery | 1994 | ||||||||
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The pseudo-barberpole (or Achim's p5[1]) is a period-5 oscillator that was found by Achim Flammenkamp on August 22, 1994.[2] With a minimum population of 15 cells, it is the smallest possible period 5 oscillator, followed by octagon 2 with 16 cells.[3][4]
On October 4, 2025, Matthias Merzenich confirmed that pseudo-barberpole is the only period-5 oscillator up to 15 cells.[5]
Occurrence
- See also: List of common oscillators
As of February 2025, this is one of two 15-cell oscillators which are yet to arise naturally from an asymmetric soup on Catagolue, with the other oscillator being the nonapole.[6] On 2022-07-06, Charity Engine discovered a C4_1 symmetric soup from which four pseudo-barberpoles emerge.[7] This is the only time a pseudo-barberpole has appeared in the final census of a non-diagonally-symmetric soup. However, the reaction in this soup evolves from fourfold rotational symmetry to eightfold symmetry, so this occurrence is not considered to be equivalent to a C1 occurrence.
| Charity Engine's C4_1 soup (click above to open LifeViewer) |
As a sparker
Due to its lack of clearance, pseudo-barberpole has very few uses as a sparker, but there are some.
| p65 pi-heptomino hassler found by Matthias Merzenich in a dimer form on March 15, 2023, based on a partial result by Mitchell Riley, and reduced by David Raucci, Jormungant, hotcrystal0, and Matthias Merzenich (click above to open LifeViewer) RLE: here Plaintext: here Catagolue: here |
Glider synthesis
Goldtiger997 found a 16-glider synthesis based on a sample soup from Adam P. Goucher's Catagolue on April 22, 2017.[8] Martin Grant found an unrelated 13-glider synthesis that can also act as a synthesis component on June 20, 2018.[9] On January 26, 2024, the cost was lowered to 10 gliders.[10][11] On February 7, 2024, Martin Grant lowered the cost to 9 gliders.[12][13]
Variants
| A radially symmetric relative of the pseudo-barberpole[14] (click above to open LifeViewer) RLE: here Plaintext: here Catagolue: here |
On October 23, 2002 Gabriel Nivasch found a period-5 oscillator that consists of four radially symmetrically arranged halves of the pseudo-barberpole, somewhat akin to Quad.[14] On 2022-04-20, Charity Engine found in a D4_x1 symmetric soup an oscillator that can be considered a tetramer of the pseudo-barberpole's ends.[15]
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See also
- Barberpole
- Smallest period 5 oscillators
- Highest volatility period-5 oscillators (containing also the volatility-0.95 variant)
References
- ↑ "Achim's p5". The Life Lexicon. Stephen Silver. Retrieved on December 3, 2018.
- ↑ Dean Hickerson's oscillator stamp collection.
- ↑ Life Period-5 Oscillators at Mark D. Niemiec's Life Page
- ↑ "Class 2 Objects Catalog". Retrieved on March 14, 2009.
- ↑ Matthias Merzenich (October 4, 2025). Re: Oscillator Discussion Thread (discussion thread) at the ConwayLife.com forums
- ↑ Small Unnatural Objects Watchlist (discussion thread) at the ConwayLife.com forums
- ↑ the attribute page, the hashsoup in question
- ↑ Goldtiger997 (April 22, 2017). Re: Soup search results (discussion thread) at the ConwayLife.com forums
- ↑ Martin Grant (June 20, 2018). Re: Synthesising Oscillators (discussion thread) at the ConwayLife.com forums
- ↑ MathAndCode (January 26, 2024). Re: Synthesising Oscillators (discussion thread) at the ConwayLife.com forums
- ↑ shinjuku (#6022117047) (January 26, 2024). Job triggered by Adam P. Goucher at GitLab Catagolue project.
- ↑ Martin Grant (Feburuary 7, 2024). Re: Synthesising Oscillators (discussion thread) at the ConwayLife.com forums
- ↑ shinjuku (#6112988643) (February 7, 2024). Job triggered by Adam P. Goucher at GitLab Catagolue project.
- ↑ 14.0 14.1 Jason Summers' all-osc pattern collection. ; x-oscs-new-p001-019.lif in jslife
- ↑ the attribute page, the soup in question
External links
- Pseudo-barberpole at the Life Lexicon
- Pseudo-barberpole at Adam P. Goucher's Catagolue
- 15P5.1 at Heinrich Koenig's Game of Life Object Catalogs
- Patterns
- Oscillators with 15 cells
- Periodic objects with minimum population 15
- Patterns with 15 cells
- Patterns found by Achim Flammenkamp
- Patterns found in 1994
- Patterns that can be constructed with 9 gliders
- Oscillators
- Barberpole variants
- Oscillators with period 5
- Oscillators with mod 5
- Oscillators with heat 16
- Oscillators with volatility 0.82
- Oscillators with strict volatility 0.82
- Oscillators with / symmetry
- Small unnatural periodic objects
- Sparkers
- Sparkers with period 5
- Domino sparkers
- Moderate sparkers
- Semi-natural periodic objects