Weekender

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 ]]
View animated image
View static image
Pattern type	Spaceship
Number of cells	36
Bounding box	18 × 12
Direction	Orthogonal
Period	7 (mod: 7)
Speed	2c/7 | 2c/7
Heat	45.1
Kinetic symmetry	Unspecified
Discovered by	David Eppstein
Year of discovery	2000
Rules Outer-totalistic rules B3/S23 – B37/S23 # of rules 21 = 2 Isotropic rules B3-ky/S23-c – B2n34cqz5ckny6-ik7/S234cekwyz5-aijq6ein7e
Glider synthesis Fewest gliders 32† Catagolue-generated RLE synthesis Uploaded synthesis RLE weekender_synth.rle †Can be constructed with 15 gliders using the reverse caber tosser universal constructor.
Pattern files Plaintext weekender.cells RLE weekender.rle
Identifiers apgcode xq7_7dfxg88gxfd7zw123u2222u321 Pentadecathlon ID 36P7H2V0.1 Eppstein ID 14105

Weekender is a 2c/7 orthogonal spaceship that was found by David Eppstein on January 12, 2000. 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). 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. On September 6, 2021, iNoMed produced a 33-glider recipe based on 35- and 34-glider recipes from a week earlier. A 32-glider synthesis was found in November 2023.

Tagalongs

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

x = 37, y = 24, rule = B3/S23 bo12bo7bo12bo$bo12bo7bo12bo$obo10bobo5bobo10bobo$bo12bo7bo12bo$bo12bo 7bo12bo$2bo3b4o3bo9bo3b4o3bo$6b4o8bo8b4o$2b4o4b4o2b5o2b4o4b4o$15bobobo bo$4bo6bo13bo6bo$5b2o2b2o6bobo6b2o2b2o$14bo2bobo2bo$14bo2bobo2bo$14bob o3bobo3$14b2o5b2o$14b2o5b2o2$16b2ob2o$15bobobobo$15bobobobo$17bobo$15b 2o3b2o! #C [[ THUMBSIZE 2 THEME 6 GRID GRIDMAJOR 0 SUPPRESS THUMBLAUNCH ]] #C [[ THUMBSIZE 2 ZOOM 8 ]]

Two weekenders followed by a tagalong (click above to open LifeViewer) RLE: here Plaintext: 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. 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.

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

See also

• Weekender distaff

External links

• Searching for Spaceships - Eppstein's paper describing the discovery of the weekender
• Weekender at the Life Lexicon
• Life (B3/S23) at David Eppstein's Glider Database
• Weekender at Adam P. Goucher's Catagolue
• 36P7H2V0.1 at Heinrich Koenig's Game of Life Object Catalogs