x66

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x66
2bo$2o$o2b3o2bo$o4b3o$b3o2b2o2$b3o2b2o$o4b3o$o2b3o2bo$2o$2bo! #C [[ THUMBSIZE 2 THEME 6 GRID GRIDMAJOR 0 SUPPRESS THUMBLAUNCH ]] #C [[ AUTOSTART ]] #C [[ HEIGHT 500 THUMBSIZE 3 ZOOM 24 GPS 4 TRACKLOOP 4 -1/2 0 ]]
Pattern type Spaceship
Number of cells 34
Bounding box 9 × 11
Direction Orthogonal
Period 4 (mod: 4)
Speed c/2 | 2c/4
Heat 31
Kinetic symmetry -c
Discovered by Hartmut Holzwart
Year of discovery 1992

x66 is a period-4 spaceship with speed c/2 orthogonal that was found by Hartmut Holzwart in July 1992.

Its name refers to the fact that every cell (alive or dead) has at most 6 live neighbours (in contrast to spaceships based on lightweight spaceships, middleweight spaceships, or heavyweight spaceships). In fact, this spaceship was found via a search with this restriction. From this follows that the spaceship is stable also in Life-like rules allowing birth or survival for a cell with 7 or 8 neighbors.

One half can be supported by a heavyweight spaceship, yielding semi-x66.

Occurrence

Main article: List of natural spaceships

As of October 2024, x66 is yet to appear naturally from soup. It has, however, appeared semi-naturally on many occasions where symmetry permits.

Glider synthesis

x66 was first synthesized by Martin Grant and Tanner Jacobi on January 11, 2015, requiring 162 gliders.[1] After the emergence of this spaceship in a symmetrical soup found by Adam P. Goucher on March 8, 2015,[2] this was drastically reduced to 13 gliders by Chris Cain,[3] and then to 12 gliders in 2018.[4] An alternative 12-glider synthesis with more stages was found by iNoMed on September 18, 2021.[5] On September 6, 2023, Carson Cheng found an 11-glider synthesis based on a partial synthesis by iNoMed.[6][7]

See also

References

  1. Martin Grant (January 11, 2015). Re: Small Spaceship Syntheses (discussion thread) at the ConwayLife.com forums
  2. flipper77 (March 8, 2015). Re: Soup search results (discussion thread) at the ConwayLife.com forums
  3. Chris Cain (March 8, 2015). Re: Soup search results (discussion thread) at the ConwayLife.com forums
  4. 2718281828 (January 15, 2018). Re: Small Spaceship Syntheses (discussion thread) at the ConwayLife.com forums
  5. iNoMed (September 18, 2021). Re: Small Spaceship Syntheses (discussion thread) at the ConwayLife.com forums
  6. Chris857 (September 7, 2023). Re: Small Spaceship Syntheses (discussion thread) at the ConwayLife.com forums
  7. shinjuku (#5030945627) (September 6, 2023). Job triggered by Adam P. Goucher at GitLab Catagolue project.

External links