Pre-pulsar spaceship

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Pre-pulsar spaceship
x = 69, y = 13, rule = B3/S23 31bo5bo$30b3o3b3o4$2b2o5b2o5b2o5b2o19b2o5b2o5b2o5b2o$o3bo3bo2bo3bo2bo 3bo3bo15bo3bo3bo2bo3bo2bo3bo3bo$o3bobob3o5b3obobo3bo15bo3bobob3o5b3obo bo3bo$o5b2o2b3ob3o2b2o5bo15bo5b2o2b3ob3o2b2o5bo$2ob3o15b3ob2o15b2ob3o 15b3ob2o$o25bo15bo25bo$bo3bo15bo3bo17bo3bo15bo3bo$2bo2bo15bo2bo19bo2bo 15bo2bo! #C [[ THUMBSIZE 2 THEME 6 GRID GRIDMAJOR 0 SUPPRESS THUMBLAUNCH ]] #C [[ AUTOSTART ]] #C [[ GPS 5 ZOOM 7 TRACKLOOP 30 0 -1/5 ]]
Pattern type Spaceship
Number of cells 128
Bounding box 73×14
Direction Orthogonal
Period 30
Mod 30
Speed c/5
Speed (unsimplified) 6c/30
Heat 131.5
Discovered by David Bell
Year of discovery 1998

Pre-pulsar spaceship (or PPS for short) is any of three different period-30 c/5 orthogonal spaceships in which a pre-pulsar is pushed by a pair of spiders. The back sparks of these spaceships can be used to perturb gliders in many different ways, allowing the easy construction of c/5 puffers.

The first pre-pulsar spaceship, the symmetric pre-pulsar spaceship (or SPPS for short, shown to the right) was found by David Bell in May 1998[1] and was based on the p15 pre-pulsar spaceship found by Noam Elkies in December 1997.

The asymmetric pre-pulsar spaceship (or APPS, shown below) was found by Alan Hensel, also in May 1998, based on a skewed version of the pre-pulsar.

The glide symmetric pre-pulsar spaceship (or GPPS, shown below) was also found by David Bell in May 1998. It is similar to the symmetric pre-pulsar spaceship but contains an extra T-tetromino between the spiders and is glide symmetric.

Martin Grant's 601-glider spider synthesis resulted in a 1212-glider synthesis for the symmetric pre-pulsar spaceship on March 8, 2019.[2]

In June 1998, David Bell found reactions to convert between the symmetric and glide-symmetric forms of the p30 pre-pulsar spaceship.[citation needed]

Image gallery

The asymmetric pre-pulsar spaceship.
Download RLE: click here
The glide symmetric pre-pulsar spaceship.
Download RLE: click here


  1. Jason Summers' jslife pattern collection. Retrieved on October 28, 2020.
  2. Adam P. Goucher (March 8, 2019). Re: Small Spaceship Syntheses (discussion thread) at the forums

External links

  • 128P30H6V0.1 at Heinrich Koenig's Game of Life Object Catalogs