# p29 pre-pulsar shuttle

p29 pre-pulsar shuttle | |||||||||||||

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Pattern type | Oscillator | ||||||||||||
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Oscillator type | Shuttle | ||||||||||||

Number of cells | 54 | ||||||||||||

Bounding box | 28 × 28 | ||||||||||||

Period | 29 | ||||||||||||

Mod | 29 | ||||||||||||

Heat | 41.5 | ||||||||||||

Volatility | 0.90 | ||||||||||||

Strict volatility | 0.90 | ||||||||||||

Discovered by | David Buckingham | ||||||||||||

Year of discovery | 1980 | ||||||||||||

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**p29 pre-pulsar shuttle** (or **prime**^{[1]}) is a period-29 shuttle oscillator discovered by David Buckingham on August 2, 1980,^{[1]} making it the first oscillator of that period to be found. In terms of its 54 cells it is the smallest known period-29 oscillator.

As shown to below, the oscillator works by combining the 15-generation, two-tub pre-pulsar shuttle mechanism used in Eureka (green) with a 14-generation pre-pulsar shuttle mechanism (red) to hassle two pre-pulsars (black). Besides this dimer, monomer and tetramer forms are also known, and several have found application and/or been synthesised over the years.

Hassling pre-pulsars in this way was the only known way of constructing period-29 oscillators until the discovery of the p29 traffic-farm hassler.

## Monomer

Two 65-cell p29 pre-pulsar shuttle monomers (click above to open LifeViewer) RLE: here Plaintext: here |

A slightly larger version of this oscillator, 56P29, with an alternate 14-generation stabilization (top) (click above to open LifeViewer) RLE: here Plaintext: hereCatagolue: here |

Replacing one half of the oscillator with an eater 4 gives a 65-cell monomer, as shown to upper left. In September 1994, Bill Gosper found that two copies of this variant could be used to hassle a pentadecathlon, resulting in p29 pentadecathlon hassler. Gosper used this domino sparker to construct the p58 toadsucker.

Like Eureka, its lower half can be shifted two cells left to make a skewed variant. The skewed variant can also have a block in the place of the lower left tub, which then emits a domino spark instead of banana spark. In 2013, Matthias Merzenich found that it supports the bouncer reaction, allowing for a period-29 independent glider reflector.^{[2]}

Another combination of two beehives and two unnamed 16-cell still lives may be used to construct a compact 56-cell version (56P29). A 43-glider synthesis for it was found by Martin Grant in October 2013,^{[3]} which has since been reduced to 32 gliders.

## Dimer

66-cell dimer (click above to open LifeViewer) |

Apart from the bent form in infobox, there exists a 66-cell linear form with two pre-pulsars in a row and two house siamese shillelaghs. It was synthesized in 28 gliders by Mark Niemiec and Heinrich Koenig in September 2007.^{[4]} (Note that the bookends, cis-mirrored tub with leg and dead spark coil work as well, and are the only stator variants that have occurred seminaturally.)

## Tetramer

An eightfold symmetric variant of this oscillator contains only tubs and pre-pulsars. It was first known to appear semi-naturally in December 2014, in a soup found by Richard Schank using apgsearch.^{[5]} As discovered by Jeremy Tan, it has a very simple 24-glider synthesis because a fourfold rotationally symmetric reaction involving four copies of lumps of muck and four pi-heptominoes produces the oscillator, plus eight blocks farther out.^{[6]} A 31-glider synthesis for the infobox form was also provided in the same post. The most common form of the oscillator in eightfold symmetry occurs approximately once every 3.5 million soups.

There is also a 184-cell variant that is basically the original p26 pre-pulsar shuttle sans four central beacons, shown below.^{[7]}

A 184-cell version of this oscillator with four pre-pulsars (click above to open LifeViewer) RLE: here Plaintext: hereCatagolue: here |

## Skew variants

These use the same mechanism as the ends of the skewed Eureka, so can similarly have their blocks replaced with tubs.

64-cell C4_1 variant (discovered by Charity Engine on 2022-05-20) (click above to open LifeViewer) Catagolue: here |

64-cell D4_x1 variant (discovered by Charity Engine on 2023-01-27) (click above to open LifeViewer) Catagolue: here |

## Gallery

### LCM oscillators

The LCM oscillators below are the smallest known oscillators where some spark cells oscillate at their period, that use the p29 pre-pulsar shuttle:

Fumarole on p29 pre-pulsar shuttle, p145 (click above to open LifeViewer) Catagolue: here |

34P7 on p29 pre-pulsar shuttle, p203 (click above to open LifeViewer) Catagolue: here |

Figure eight on p29 pre-pulsar shuttle, p232, tied with figure eight on p58 pi-heptomino hassler (click above to open LifeViewer) RLE: here Plaintext: hereCatagolue: here |

42P9 on p29 pre-pulsar shuttle, p261 (click above to open LifeViewer) Catagolue: here |

## See also

- p26 pre-pulsar shuttle
- p28 pre-pulsar shuttle
- p47 pre-pulsar shuttle
- p58 pre-pulsar shuttle
- p55 pre-pulsar hassler

## References

- ↑
^{1.0}^{1.1}Dean Hickerson's oscillator stamp collection. Retrieved on December 8, 2019. - ↑ Matthias Merzenich (August 28, 2013). Re: p29 dependent reflector (discussion thread) at the ConwayLife.com forums
- ↑ Martin Grant (October 11, 2013). Re: Synthesising Oscillators (discussion thread) at the ConwayLife.com forums
- ↑ More Glider Constructions at Game of Life News. Posted by Heinrich Koenig on September 16, 2007.
- ↑ Richard Schank (December 18, 2014). Re: Soup search results (discussion thread) at the ConwayLife.com forums
- ↑ Jeremy Tan (June 7, 2019). Re: Synthesising Oscillators (discussion thread) at the ConwayLife.com forums
- ↑ Adam P. Goucher (January 21, 2010). Re: One Bit Difference (discussion thread) at the ConwayLife.com forums

## External links

### Adam P. Goucher's Catagolue

- p29 pre-pulsar shuttle (D2_x 54-cell dimer)
- p29 pre-pulsar shuttle (65-cell monomer with Eater 4)
- p29 pre-pulsar shuttle (65-cell skewed monomer with block)
- 56P29 (56-cell monomer)
- p29 pre-pulsar shuttle (66-cell C2_1 linear dimer, though near 68-cell D4_+1 variant and far 60-cell D4_+1 variant are seminatural)
- p29 pre-pulsar shuttle (64-cell D8_1 tetramer)
- p29 pre-pulsar shuttle (184-cell D8_1 symmetric tetramer)
- p29 pre-pulsar shuttle (seminatural 64-cell C4_1 skewed tetramer)
- p29 pre-pulsar shuttle (seminatural 64-cell D4_x1 skewed tetramer)

### Others

- 54P29.1 at Heinrich Koenig's Game of Life Object Catalogs
- New Oscillators at Game of Life News. Posted by Heinrich Koenig on January 08, 2009.

- Patterns
- Oscillators with 54 cells
- Periodic objects with minimum population 54
- Patterns with 54 cells
- Patterns found by David Buckingham
- Patterns found in 1980
- Patterns that can be constructed with 25 gliders
- Patterns that can be constructed with 24 gliders
- Oscillators
- Shuttles
- Oscillators with period 29
- Prime-period oscillators
- Oscillators with mod 29
- Oscillators with heat 41
- Oscillators with volatility 0.90
- Oscillators with strict volatility 0.90
- Patterns with bilateral diagonal symmetry
- Sparkers
- Sparkers with period 29
- Strong sparkers
- Pre-pulsar shuttle oscillators