Lightweight spaceship

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Lightweight spaceship
Pattern type Spaceship
Family XWSS
Number of cells 9
Bounding box 5 × 4
Frequency class 11.2
Direction Orthogonal
Period 4
Mod 2
Speed c/2
Speed (unsimplified) 2c/4
Heat 11
Discovered by John Conway
Year of discovery 1970

The lightweight spaceship (commonly abbreviated to LWSS) or (rarely) small fish[1] is the smallest orthogonal spaceship, and the second most common spaceship after the glider. It moves at speed c/2 and has period 4 (and is therefore often referred to as 2c/4). It was found by John Conway in 1970.


In April 1992, David Bell found a tagalong for two lightweight spaceships (or two middleweight spaceships or two heavyweight spaceships). It can be extended indefinitely by attaching it to the back of itself. Interestingly, a hivenudger with symmetric rear (that is, both rear spaceships being of same "weight") can pull this tagalong.

x = 25, y = 19, rule = b3/s23 21bo3b$18b4o3b$13bo2bob2o5b$13bo11b$4o8bo3bob2o5b$o3bo5b2ob2obobob5o$o 9b2obobobo2b5o$bo2bo2b2o2bo3b3o2bob2ob$6bo2bob2o12b$6bo4b2o12b$6bo2bob 2o12b$bo2bo2b2o2bo3b3o2bob2ob$o9b2obobobo2b5o$o3bo5b2ob2obobob5o$4o8bo 3bob2o5b$13bo11b$13bo2bob2o5b$18b4o3b$21bo! #C [[ THUMBSIZE 2 THEME 6 GRID GRIDMAJOR 0 SUPPRESS THUMBLAUNCH ]] #C [[ TRACKLOOP 4 -1/2 0 THUMBSIZE 2 GPS 4 ZOOM 12 HEIGHT 600 ANGLE 90 AUTOSTART ]]
Tagalong for two lightweight spaceships (click above to open LifeViewer)
RLE: here Plaintext: here


x = 78, y = 45, rule = B3/S23 76bo$75bo$75b3o20$58bobo$59b2o8bobo$59bo9b2o$70bo2$12bo$11bo$o10b3o$b 2o$2o$19bo18bo$20bo15bobo$18b3o16b2o2$53bo$32bo19b2o$12b2o17b2o19bobo$ 11b2o18bobo$13bo$41b3o$22b3o18bo$24bo17bo$23bo! #C [[ THUMBSIZE 2 THEME 6 GRID GRIDMAJOR 0 SUPPRESS THUMBLAUNCH ]] #C [[ ZOOM 8 WIDTH 800 HEIGHT 400 THEME Book AUTOSTART GPS 12 T 0 PAUSE 1 T 12 PAUSE 7 T 75 PAUSE 1 LOOP 76 ]]
Four 3G syntheses for the LWSS (click above to open LifeViewer)

A number of different ways to construct a LWSS can be found in Mark Niemiec's glider synthesis database;[2] above are shown three-glider syntheses.

A three-object one-glider seed for the lightweight spaceship, consisting of two blocks and a beehive, is used in the pattern Patterns/Life/Breeders/switch-engine-breeder-MR.rle included in Golly's pattern collection. The seed constellation itself can be constructed with four gliders,[3] leading to a way of constructing the LWSS using 5 gliders.

A different one-glider seed that fits inside a 12 × 12 square can be found in the octohash database;[4] it is a constellation of a blinker and an eater 1, itself constructible with four gliders.[5] There are 60 matches in the octo3obj database which are clean one-glider seeds for the LWSS.[6]

x = 15, y = 18, rule = B3/S23 9bo$8bo$8b3o7$9b2o$9b2o3$13b2o$bo11b2o$obo$obo$bo! #C [[ THUMBSIZE 2 THEME 6 GRID GRIDMAJOR 0 SUPPRESS THUMBLAUNCH ]] #C [[ ZOOM 8 Y 8 THEME Book AUTOSTART GPS 20 T 0 PAUSE 1 T 159 PAUSE 1 LOOP 160 ]]
A three-object 1G seed for the LWSS (click above to open LifeViewer)
x = 11, y = 10, rule = B3/S23 7b2o$8bo$5b3o$3o2bo4$8b2o$8bobo$8bo! #C [[ THUMBSIZE 2 THEME 6 GRID GRIDMAJOR 0 SUPPRESS THUMBLAUNCH ]] #C [[ ZOOM 8 THEME Book AUTOSTART GPS 20 T 0 PAUSE 1 T 63 PAUSE 1 LOOP 64 ]]
A two-object 1G seed for the LWSS (click above to open LifeViewer)


See also: List of common spaceships

Random soups investigated by Achim Flammenkamp emitted one LWSS for approximately every 615 gliders.[7] The LWSS is also the eighteenth most common object on Adam P. Goucher's Catagolue.[8]

There are 731 results in the octohash database,[note 1] 6563 results in the octo3obj database,[note 2] and 1009 results in the octo3g database[note 3] with at least one escaping LWSS.

See also


  1. There are two collisions, each with two escaping LWSSes. One collision (headerless RLE 8b2o$9bo$b2o6bobo$obo2b2o3b2o$2o2b2o$6bo!) has final population 158. The other collision (b2o$obo$2o6b2o$9bo$9bobo$10b2o2$12bo$11b2o$11bobo!) has final population alternating between 367 and 373.
  2. There are 28 results where two lightweight spaceships escape.
  3. There is one collision (headerless RLE obo$b2o$bo75$75bo$76b2o$75b2o$80bo$79b2o$79bobo!) with two escaping lightweight spaceships. The final population is 377.


  1. "Small fish". The Life Lexicon. Stephen Silver. Retrieved on June 10, 2009.
  2. The 1 nine-bit spaceship at Mark D. Niemiec's Life Page (download pattern file: ss/9lw.rle)
  3. xs14_696y6oozy5cc at Adam P. Goucher's Catagolue (pseudo-object)
  4. Repository on GitHub
  5. xp2_354cxs at Adam P. Goucher's Catagolue (pseudo-object)
  6. Dave Greene (October 21, 2022). Re: Octohash fingerprints (discussion thread) at the forums
  7. "Spontaneous appeared Spaceships out of Random Dust". Achim Flammenkamp (December 9, 1995). Retrieved on August 18, 2011.
  8. Adam P. Goucher. "Statistics". Catagolue. Retrieved on June 24, 2016.

External links