A relay is an oscillator in which spaceships (typically gliders) travel in a loop. The simplest example is the p60 glider shuttle shown below using two pentadecathlons. Pulling the pentadecathlons further apart allows any period of the form 60 + 120n to be achieved. This is the simplest proof of the existence of oscillators of arbitrarily large period.
|pentadecathlon relay (p60 glider shuttle)|
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RLE: here Plaintext: here