Weekender

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Weekender
#N Weekender #O David Eppstein #C An orthogonal period 7 spaceship with speed 2c/7. #C www.conwaylife.com/wiki/Weekender x = 16, y = 11, rule = B3/S23 bo12bo$bo12bo$obo10bobo$bo12bo$bo12bo$2bo3b4o3bo$6b4o$2b4o4b4o2$4bo6bo $5b2o2b2o! #C [[ THUMBSIZE 2 THEME 6 GRID GRIDMAJOR 0 SUPPRESS THUMBLAUNCH ]] #C [[ AUTOSTART ]] #C [[ GPS 7 TRACKLOOP 7 0 -2/7 THUMBSIZE 2 ]]
Pattern type Spaceship
Number of cells 36
Bounding box 18×12
Direction Orthogonal
Period 7
Mod 7
Speed 2c/7
Speed (unsimplified) 2c/7
Heat 45.1
Discovered by David Eppstein
Year of discovery 2000

Weekender is a 2c/7 orthogonal spaceship that was found by David Eppstein on January 12, 2000.[1] Before the discovery of scholar in 2019, n weekenders pulling n-1 tagalongs constituted the only known spaceships with speed 2c/7, besides self-sustaining loops of weekender conduits. These were the only known period-7 spaceships until the discovery of lobster in 2011, loafer in 2013 and spaghetti monster in 2016.

Despite the relative simplicity of its components, a glider synthesis for the weekender had been elusive since its discovery. A weekender synthesis was completed on January 25, 2015, 15 years after its discovery (and coincidentally, on a weekend).[2] On September 26, 2015, Chris Cain announced a p444 weekender gun based on a 79-glider synthesis, as well as a p451/p457+ glider-to-weekender converter.[3]

Tagalongs

On April 27, 2000, Stephen Silver found a tagalong for a pair of weekenders, as shown below.

Two weekenders followed by a tagalong
RLE: here

On December 6, 2020, John Winston Garth found doo-dah, a small period-21 tagalong for a single weekender, which in its simplest phase consists entirely of two R-pentomino descendants.[4][5] The spaceship was found using a combination of ikpx2 and apgsearch, with partial results from the former being inputted into the latter via ikpx2's "standard input" feature, with the goal of searching higher-period spaceships and puffers. Garth chose the name "doo-dah" for the tagalong.[6]

Soon after, Matthias Merzenich discovered that a component from the side of 186P7H2V0 can attach to a weekender.[7] On March 19, 2021, Merzenich discovered a width-22 symmetric tagalong for a single weekender[8] and proved that this is the only such period-7 symmetric tagalong at that width.[9]

See also

References

  1. Jason Summers' jslife pattern collection.
  2. Martin Grant (January 25, 2015). Re: Small Spaceship Syntheses (discussion thread) at the ConwayLife.com forums
  3. Chris Cain (September 26, 2015). Re: Small Spaceship Syntheses (discussion thread) at the ConwayLife.com forums
  4. J. H. Yu (December 6, 2020). Re: Spaceship Discussion Thread (discussion thread) at the ConwayLife.com forums
  5. Aidan F. Pierce (December 6, 2020). Re: Spaceship Discussion Thread (discussion thread) at the ConwayLife.com forums
  6. John Winston Garth (December 6, 2020). Message in #cgol on the Conwaylife Lounge Discord server
  7. Matthias Merzenich (December 8, 2020). Re: Spaceship Discussion Thread (discussion thread) at the ConwayLife.com forums
  8. Matthias Merzenich (March 19, 2021). Re: Spaceship Discussion Thread (discussion thread) at the ConwayLife.com forums
  9. Matthias Merzenich (March 21, 2021). Re: Spaceship Discussion Thread (discussion thread) at the ConwayLife.com forums

External links

  • 36P7H2V0.1 at Heinrich Koenig's Game of Life Object Catalogs