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| {{Glossary}}
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| A '''reflector''' is a [[still life|stable]] or [[oscillator|oscillating]] pattern that can reflect some specific type of [[spaceship]] (usually a [[glider]]) without suffering permanent damage. The first known reflector was the [[pentadecathlon]], which can function as a 180-degree glider reflector as in [[relay]]. Other examples include the [[buckaroo]], the [[twin bees shuttle]] and some oscillators based on the [[traffic jam]] reaction. Glider [[gun]]s can also be made into reflectors, although these are mostly rather large.
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| In September [[:Category:Patterns found in 1998|1998]] [[Noam Elkies]] found some fast small-period glider reflectors based on an arrangement of a [[block]], [[boat]] and [[eater 1]] that can be used in conjunction with [[pipsquirter 1]], [[pipsquirter 2]], or [[figure eight]] to create a 90-degree glider reflector of period 6, 7, or 8, respectively. A more complicated construction allows a period 5 version of the reflector (which, as had been anticipated, soon led to a [[true period]] 55 gun - see [[Quetzal]]). A variant of the [[pentadecathlon]] can also be used to construct a period 15 reflector in this way.
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| ==Stable reflectors==
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| {{main|Stable reflector}}
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| Stable reflectors are special in that, if they satisfy certain conditions, they can be used to construct oscillators of all sufficiently large periods. It was known for some time that stable reflectors were possible (see [[universal constructor]]), but no one was able to construct an explicit example until [[Paul Callahan]] did so in October [[:Category:Patterns found in 1996|1996]].
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| ==External links==
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| {{LinkWeisstein|Reflector.html}}
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| {{LinkLexicon|lex_r.htm#reflector}}
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