A Life oscillator is a nonconstant periodic orbit of the Conway's Game of Life update function . Its period is the least positive integer for which , comparing the entire live-cell set at the same coordinates. A configuration that never changes is instead a fixed point; a Life glider is not a Life oscillator on the infinite board because it returns at displaced coordinates. The Life blinker has period two.[ref]
https://github.com/nathanieljohnston/game-of-life-book/blob/master/oscillators.tex. Johnston and Greene, chapter 3: oscillators and their periods
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