Pure glider generator

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A pure glider generator (or simply glider generator) is a pattern that evolves into one or more gliders and nothing else.[1][2] 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).

However, there are so many easy-to-find pure glider generators that it's impossible to catalogue them all, unless some extra constraints are added (for example being glider-constructible, or being made out of just blocks, or being a one-cell-thick pattern).[3][4][5]

Examples

x = 12, y = 9, rule = B3/S23 4b4o2$2b8o2$12o2$2b8o2$4b4o! #C [[ THUMBSIZE 2 THEME 6 GRID GRIDMAJOR 0 SUPPRESS THUMBLAUNCH ]] #C [[ AUTOSTART THUMBSIZE 2 GPS 5 PAUSE 2 LOOP 50 ]]
The 4-8-12 diamond
(click above to open LifeViewer)
RLE: here Plaintext: here
x = 4, y = 7, rule = B3/S23 2bo$bobo$o2bo$b2o$o2bo$obo$bo! #C [[ THUMBSIZE 2 THEME 6 GRID GRIDMAJOR 0 SUPPRESS THUMBLAUNCH ]] #C [[ AUTOSTART THUMBSIZE 2 GPS 5 PAUSE 2 LOOP 50 ]]
The bi-loaf
(click above to open LifeViewer)
RLE: here Plaintext: here
x = 7, y = 7, rule = B3/S23 2bo$2o$2b2o$bo3bo$3b2o$5b2o$4bo! #C [[ THUMBSIZE 2 THEME 6 GRID GRIDMAJOR 0 SUPPRESS THUMBLAUNCH ]] #C [[ AUTOSTART THUMBSIZE 2 GPS 5 PAUSE 2 LOOP 50 ]]
The bi-clock
(click above to open LifeViewer)
RLE: here Plaintext: here

The 4-8-12 diamond and the bi-loaf[note 1] are two pure glider generators found by the Honeywell group in 1971.[6] 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.[7] It consists of two closely placed clocks, and evolves into two gliders in two generations.

x = 68, y = 46, rule = B3/S23 17bo$14bo3bo3b2o$16bo3bo$15bo3bo3b2o$13bo3bo3bo$8bo2bo2bo3bo3bobo$10bo 5bo3bo$4bo3bo6bo3bo$2bo3bo5bo4bo3bo$bo3bo3bo3bo4bo47bo$3bo3bo53bobo3bo $o3bo3bo3bobo3bo42bo3bo$2bo3bo3bo5bo47bo$bo3bo3bo5bo46bo3bo$3bo3bo3bob o46bo2bo$o3bo3bo6bo22bo19bo$2bo3bo3bo3bo8bo4bo3bo2bo3bo3b2o2bobo2b2o3b o3bo2bo$5bo3bo2bo5bo6bo3bobo5bo3bo13bo3bo3bo$bobo3bo5bo2bo3bo2bo3bo8bo 3bo3b2o2bo2b2o3bo3bo$3bo7bo5bo3bo4bo5bobo3bo3bo5bo5bo3bo3bo$bo3bobo7bo 3bo4bo3bo2bo3bo3bo3bobo5bobo3bo3bo$10bo2bo4bo3bo2bo11bo3bo13bo3bo$3bo 7bo4bo3bo6b2o2bobo2bo3bo6bobo6bo3bo$bo2bobo6bo3bo3bo16bo3bobo4bobo2bo 3bo$2bo6bo9bo5bo4bo3bo4bo7bo3bo5bo$7bo3bo4bobo4bo3bo4bo9bobo3bo$6bo3bo 4bo8bo3bo2bo3bobo3bo4bo3bo2bobo$8bo3bo6bo2bo3bo6bo4bo6bo3bo8bo$5bo3bo 3bo4bo2bo3bo3bo6bo3bo2bo3bo3bo3bo$7bo3bo4bo6bo3bo4bo2bo3bo4bo3bo3bo3bo bo$6bo3bo2bo3bo3bo2bo3bo2bo5bo3bo4bo3bo3bo$8bo6bo10bo7bo3bo6bo3bo5bo$ 36bo3bo2bo3bo3bo$8bobo3bo20bo3bo8bo4bo$11bo25bo14bo2bobo$9bo3bo36bo6bo bo$8bo3bo36bo5bo3bo$10bo3bo37bo3bo$7bo3bo42bo3bo$9bo3bo39bo3bo$8bo3bo 38bo3bo3bo$10bo41bo3bo3bo$54bo3bo$53bo3bo$55bo3bo$56bo! #C [[ THUMBSIZE 2 THEME 6 GRID GRIDMAJOR 0 SUPPRESS THUMBLAUNCH ]] #C [[ ZOOM 8 THUMBSIZE 2 WIDTH 500 HEIGHT 500 LOOP 90 AUTOSTART PAUSE 5 GPS 10 ]]
Mirage
(click above to open LifeViewer)
RLE: here Plaintext: here
x = 68, y = 46, rule = B3/S23 17bo$14bo3bo3b2o$16bo3bo$15bo3bo3b2o$13bo3bo3bo$14bo3bo3bobo$16bo3bo$ 4bo10bo3bo$2bo3bo10bo3bo$bo3bo3bo8bo47bo$3bo3bo53bobo3bo$o3bo3bo52bo3b o$2bo3bo3bo53bo$bo3bo3bo52bo3bo$3bo3bo3bo51bo$4bo3bo29bo19bo$2bo3bo3bo 12bo4bo6bo3bo3b2o7b2o3bo3bo$5bo3bo8bo6bo3bo7bo3bo13bo3bo$bobo3bo8bo3bo 2bo3bo8bo3bo3b2o5b2o3bo3bo$3bo13bo3bo4bo7bo3bo3bo11bo3bo3bo$bo3bobo7bo 3bo4bo3bo6bo3bo3bobo5bobo3bo3bo$18bo3bo2bo11bo3bo13bo3bo$16bo3bo6b2o7b o3bo6bobo6bo3bo$17bo3bo16bo3bo6bobo2bo3bo$9bo9bo5bo13bo7bo3bo5bo$7bo3b o4bobo4bo3bo16bo3bo$6bo3bo13bo3bo6bobo8bo3bo$8bo3bo9bo3bo11bo6bo3bo$5b o3bo3bo7bo3bo3bo6bo3bo2bo3bo3bo$7bo3bo11bo3bo7bo3bo4bo3bo3bo$6bo3bo2bo 7bo2bo3bo8bo3bo4bo3bo$8bo17bo7bo3bo6bo3bo$36bo3bo6bo3bo$8bobo24bo3bo8b o$11bo25bo17bobo$9bo3bo43bobo$8bo3bo42bo3bo$10bo3bo37bo3bo$7bo3bo42bo 3bo$9bo3bo39bo3bo$8bo3bo38bo3bo3bo$10bo41bo3bo3bo$54bo3bo$53bo3bo$55bo 3bo$56bo! #C [[ THUMBSIZE 2 THEME 6 GRID GRIDMAJOR 0 SUPPRESS THUMBLAUNCH ]] #C [[ ZOOM 8 THUMBSIZE 2 WIDTH 500 HEIGHT 480 LOOP 90 AUTOSTART PAUSE 5 GPS 10 ]]
A variant without unnecessary sparks
between essential glider-making clusters
(click above to open LifeViewer)
RLE: here Plaintext: here

Mirage (or Fata Morgana) is a pure glider generator in which many sparse cells quickly create 13 gliders. Eight of those gliders construct a Gosper glider gun at generation 34, but the remaining five destroy the gun by generation 73.[8] Similar patterns based on other glider syntheses can be constructed.[9]

x = 6, y = 2, rule = B3/S23 6o$5o! #C [[ THUMBSIZE 2 THEME 6 GRID GRIDMAJOR 0 SUPPRESS THUMBLAUNCH ]] #C [[ AUTOSTART THUMBSIZE 2 GPS 5 PAUSE 2 LOOP 25 ]]
An undecomino that evolves into a single glider
(click above to open LifeViewer)
RLE: here Plaintext: here
x = 15, y=9, rule = B3/S23 2bo$2bo$3o2$6b3o$7bo$12b3o$12bo$12bo! #C [[ THUMBSIZE 2 THEME 6 GRID GRIDMAJOR 0 SUPPRESS THUMBLAUNCH ]] #C [[ AUTOSTART THUMBSIZE 2 GPS 5 PAUSE 2 LOOP 50 ]]
Evolves into four gliders,
one travelling in each direction
(click above to open LifeViewer)
RLE: here Plaintext: here

The two examples above from unknown source have been added to this LifeWiki article since 2009.

A pure glider generator was featured on Randall Munroe's webcomic xkcd as a tribute to John Conway, the inventor of Game of Life.[10]

See also

Notes

  1. 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

  1. Pure glider generator at the Life Lexicon
  2. twinb7 (March 2nd, 2014). Pure Glider Generators (discussion thread) at the ConwayLife.com forums
  3. Dave Greene (March 8th, 2014). Re: Pure Glider Generators (discussion thread) at the ConwayLife.com forums
  4. knightlife (April 4th, 2013). Blockic splitters (discussion thread) at the ConwayLife.com forums
  5. twinb7 (March 5th, 2014). 1-Dimensional Patterns (discussion thread) at the ConwayLife.com forums
  6. Robert Wainwright (March 1971). Lifeline, vol 1, page 3.
  7. Robert Wainwright (June 1971). Lifeline, vol 2, page 5.
  8. Alan Hensel's lifep.zip pattern collection.
  9. Bob Shemyakin (August 17, 2014). Re: Pure Glider Generators (discussion thread) at the ConwayLife.com forums
  10. Randall Munroe (April 13, 2020). "2293: RIP John Conway". Retrieved on December 18, 2020.

External links