Stable reflector: Difference between revisions
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New page: A stable reflector is any arrangement of still lifes that can absorb a glider, releasing one or more gliders and restoring itself in the process. The first reflectors were found by Pau... |
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A stable reflector is | A '''stable reflector''' is a [[reflector]] composed entirely of [[still life]]s. The first stable reflectors were found by Paul Callahan in 1996. | ||
==Types of stable reflectors== | |||
There are several distinct categories of stable reflector: | |||
* 'Callahan' reflector - A reflector that temporarily creates an unwanted still-life and later destroys it. | * 'Callahan' reflector - A reflector that temporarily creates an unwanted still-life and later destroys it. | ||
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* Direct reflector - A reflector that does not contain a Herschel track. | * Direct reflector - A reflector that does not contain a Herschel track. | ||
==Records== | |||
Ideally, stable reflectors should be as small and fast as possible. : | |||
== Records == | |||
Ideally, stable reflectors should be as small and fast as possible. | |||
* Smallest 90° reflector: [http://myweb.tiscali.co.uk/calcy/life/reflectors.htm#sect9] | * Smallest 90° reflector: [http://myweb.tiscali.co.uk/calcy/life/reflectors.htm#sect9] | ||
* Fastest 90° reflector: [http://myweb.tiscali.co.uk/calcy/life/reflectors.htm#sect13] | * Fastest 90° reflector: [http://myweb.tiscali.co.uk/calcy/life/reflectors.htm#sect13] | ||
* Smallest 180° reflector: [[rectifier]] | * Smallest 180° reflector: [[rectifier]] | ||
* Fastest | * Fastest 180° reflector: [[rectifier]] | ||
The third record is debatable, since the [[boojum reflector]] has a smaller bounding box across all phases; the rectifier has the smallest quiescent configuration. The terms 'active' and 'passive' bounding box should be used to avoid confusion. | The third record is debatable, since the [[boojum reflector]] has a smaller bounding box across all phases; the rectifier has the smallest quiescent configuration. The terms 'active' and 'passive' bounding box should be used to avoid confusion. | ||
===Prizes=== | |||
Dave Greene has offered two $50 prizes for stable reflectors: | |||
* Find a stable glider reflector that fits inside a 50×50 bounding box. | |||
* Find a stable glider reflector that fits inside a 35×35 bounding box. | |||
* Find a stable glider reflector that fits inside a 50 | |||
* Find a stable glider reflector that fits inside a 35 | |||
==Staged-recovery systems== | |||
The staged-recovery system was invented by Dave Greene, when he incorporated it into his [[highway robber]] and stable [[Heisenburp]] patterns. In 2009, Adam P. Goucher built two 'Callahan' reflectors using a staged-recovery system. | The staged-recovery system was invented by Dave Greene, when he incorporated it into his [[highway robber]] and stable [[Heisenburp]] patterns. In 2009, Adam P. Goucher built two 'Callahan' reflectors using a staged-recovery system. | ||
Revision as of 21:31, 24 May 2009
A stable reflector is a reflector composed entirely of still lifes. The first stable reflectors were found by Paul Callahan in 1996.
Types of stable reflectors
There are several distinct categories of stable reflector:
- 'Callahan' reflector - A reflector that temporarily creates an unwanted still-life and later destroys it.
- 'Buckingham' reflector - A reflector that temporarily destroys a necessary still-life and later reconstructs it.
- Direct reflector - A reflector that does not contain a Herschel track.
Records
Ideally, stable reflectors should be as small and fast as possible. :
- Smallest 90° reflector: [1]
- Fastest 90° reflector: [2]
- Smallest 180° reflector: rectifier
- Fastest 180° reflector: rectifier
The third record is debatable, since the boojum reflector has a smaller bounding box across all phases; the rectifier has the smallest quiescent configuration. The terms 'active' and 'passive' bounding box should be used to avoid confusion.
Prizes
Dave Greene has offered two $50 prizes for stable reflectors:
- Find a stable glider reflector that fits inside a 50×50 bounding box.
- Find a stable glider reflector that fits inside a 35×35 bounding box.
Staged-recovery systems
The staged-recovery system was invented by Dave Greene, when he incorporated it into his highway robber and stable Heisenburp patterns. In 2009, Adam P. Goucher built two 'Callahan' reflectors using a staged-recovery system.