Pure glider generator
A pure glider generator (or simply glider generator) is a pattern that evolves into one or more gliders and nothing else. They are part of the cosmological classification of Life patterns. There was interest in this scheme early on, and within it on pure glider generators in particular (they were reported on quite frequently in the early issues of Lifeline, for example), but nowadays they are no longer considered important.
Examples
The 4-8-12 diamond and the bi-loaf[note 1] are two pure glider generators found by the Honeywell group in 1971.[1] The former evolves into four gliders (one heading in each diagonal direction) in 15 generations, while the latter yields two after four ticks. Gliders from the bi-loaf run in opposite ways along the diagonal that is closest to the great axis of the pattern. E.g. when the great axis is NNE-SSW, the gliders' directions are northeast & southwest.
The bi-clock is a later example found by Dale Edwin Cole in the same year.[2] It consists of two clocks, and evolves into two gliders in two generations.
Other instances can also be found elsewhere.
An undecomino that evolves into a single glider (click above to open LifeViewer) RLE: here Plaintext: here |
Evolves into four gliders, one travelling in each direction (click above to open LifeViewer) RLE: here Plaintext: here |
A pure glider generator is featured on xkcd as a tribute to John Conway.[3]
See also
Notes
- ↑ The term "bi-loaf" is now a collective description of the still lifes consisting of two loaves, e.g. the half-bakery and the loaf back tie loaf.
References
- ↑ Robert Wainwright (March 1971). Lifeline, vol 1.
- ↑ Robert Wainwright (June 1971). Lifeline, vol 2.
- ↑ "xkcd: RIP John Conway". Retrieved on December 18, 2020.
External links
- 4-8-12 diamond at the Life Lexicon
- Bi-loaf at the Life Lexicon
- Bi-clock at the Life Lexicon