# Difference between revisions of "Oscillator"

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==Important oscillators by period== | ==Important oscillators by period== | ||

− | A list of the first-discovered oscillator of each period, as well the current smallest-known oscillator of that period, is provided here. Note that only non-trivial oscillators are considered here, in the sense that there must be at least one cell that oscillates at the full period. In some cases, it is not known for certain what the first-discovered oscillator of a given period is, and in such situations all possible candidates are listed. For any period 61 or greater an oscillator can be constructed using the Herschel track method. In April, {{year|2013}} [[Mike Playle]] found a small 90-degree [[stable reflector]] that allows oscillators of all periods 43 or greater to be constructed. | + | A list of the first-discovered oscillator of each period, as well the current smallest-known oscillator of that period, is provided here. Note that only non-trivial oscillators are considered here, in the sense that there must be at least one cell that oscillates at the full period. In some cases, it is not known for certain what the first-discovered oscillator of a given period is, and in such situations all possible candidates are listed. For any period 61 or greater an oscillator can be constructed using the Herschel track method. In April, {{year|2013}} [[Mike Playle]] found a small 90-degree [[stable reflector]] known as the [[Snark]] that allows oscillators of all periods 43 or greater to be constructed. |

{| class="wikitable" style="margin-left:auto;margin-right:auto;" | {| class="wikitable" style="margin-left:auto;margin-right:auto;" | ||

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! [[:Category:Oscillators with period 2|2]] | ! [[:Category:Oscillators with period 2|2]] | ||

| [[blinker]] | | [[blinker]] | ||

− | | [[ | + | | [[John Conway]] |

| [[:Category:Patterns found in 1970|1970]] | | [[:Category:Patterns found in 1970|1970]] | ||

| | | | ||

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! [[:Category:Oscillators with period 4|4]] | ! [[:Category:Oscillators with period 4|4]] | ||

| [[pinwheel]] | | [[pinwheel]] | ||

− | | [[ | + | | [[Simon Norton]] |

| 1970 | | 1970 | ||

| | | | ||

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! [[:Category:Oscillators with period 5|5]] | ! [[:Category:Oscillators with period 5|5]] | ||

| [[octagon 2]] | | [[octagon 2]] | ||

− | | [[ | + | | [[Sol Goodman]], [[Arthur Taber]] |

| [[:Category:Patterns found in 1971|1971]] | | [[:Category:Patterns found in 1971|1971]] | ||

| | | | ||

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! [[:Category:Oscillators with period 6|6]] | ! [[:Category:Oscillators with period 6|6]] | ||

| [[$rats]] | | [[$rats]] | ||

− | | [[ | + | | [[David Buckingham]] |

| [[:Category:Patterns found in 1972|1972]] | | [[:Category:Patterns found in 1972|1972]] | ||

| | | | ||

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! [[:Category:Oscillators with period 14|14]] | ! [[:Category:Oscillators with period 14|14]] | ||

| [[tumbler]] | | [[tumbler]] | ||

− | | George Collins | + | | [[George Collins]] |

| 1970 | | 1970 | ||

| | | | ||

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! [[:Category:Oscillators with period 17|17]] | ! [[:Category:Oscillators with period 17|17]] | ||

| [[54P17.1]] | | [[54P17.1]] | ||

− | | [[ | + | | [[Dean Hickerson]] |

| [[:Category:Patterns found in 1997|1997]] | | [[:Category:Patterns found in 1997|1997]] | ||

| | | | ||

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! [[:Category:Oscillators with period 23|23]] | ! [[:Category:Oscillators with period 23|23]] | ||

| [[David Hilbert]] | | [[David Hilbert]] | ||

− | | Luka Okanishi, Aidan F. Pierce | + | | [[Luka Okanishi]], [[Aidan F. Pierce]] |

| {{year|2019}} | | {{year|2019}} | ||

| | | | ||

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! [[:Category:Oscillators with period 33|33]] | ! [[:Category:Oscillators with period 33|33]] | ||

| [[258P3 on Achim's p11]] | | [[258P3 on Achim's p11]] | ||

− | | Noam Elkies, [[ | + | | Noam Elkies, [[Achim Flammenkamp]] |

| 1997 | | 1997 | ||

| | | | ||

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! [[:Category:Oscillators with period 37|37]] | ! [[:Category:Oscillators with period 37|37]] | ||

| [[Beluchenko's p37]] | | [[Beluchenko's p37]] | ||

− | | [[ | + | | [[Nicolay Beluchenko]] |

| [[:Category:Patterns found in 2009|2009]] | | [[:Category:Patterns found in 2009|2009]] | ||

| | | | ||

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! [[:Category:oscillators with period 53|53]] | ! [[:Category:oscillators with period 53|53]] | ||

| [[p53 glider loop]] | | [[p53 glider loop]] | ||

− | | | + | | Mike Playle |

| [[:Category:patterns found in 2013|2013]] | | [[:Category:patterns found in 2013|2013]] | ||

| | | | ||

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! [[:Category:Oscillators with period 57|57]] | ! [[:Category:Oscillators with period 57|57]] | ||

| [[p57 Herschel loop 1]] | | [[p57 Herschel loop 1]] | ||

− | | [[ | + | | [[Dietrich Leithner]] |

| 1997 | | 1997 | ||

| | | | ||

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! [[:Category:oscillators with period 312|312]] | ! [[:Category:oscillators with period 312|312]] | ||

| period-tripled [[p104 gun]] | | period-tripled [[p104 gun]] | ||

− | | Dave Greene | + | | [[Dave Greene]] |

| 2004 | | 2004 | ||

| | | |

## Revision as of 16:17, 29 November 2019

An **oscillator** is a pattern that is a predecessor of itself. That is, it is a pattern that repeats itself after a fixed number of generations (known as its period). The term is usually restricted to finite patterns that are not still lifes, though still lifes may be thought of as oscillators with period 1. An oscillator is divided into a rotor (the individual cells that actually oscillate) and a stator (the cells which remain alive throughout its whole period).

Cellular automaton theory recognizes shift periodicity, which refers to a configuration reappearing in shifted form after a lapse of one or more generations. Without the shift, it is an oscillator, but if it moves it would be called a spaceship.

## Important oscillators by period

A list of the first-discovered oscillator of each period, as well the current smallest-known oscillator of that period, is provided here. Note that only non-trivial oscillators are considered here, in the sense that there must be at least one cell that oscillates at the full period. In some cases, it is not known for certain what the first-discovered oscillator of a given period is, and in such situations all possible candidates are listed. For any period 61 or greater an oscillator can be constructed using the Herschel track method. In April, 2013 Mike Playle found a small 90-degree stable reflector known as the Snark that allows oscillators of all periods 43 or greater to be constructed.

## See also

## External links

- Oscillator at Wikipedia

- Oscillator at the Life Lexicon