Gemini

Gemini is the first oblique spaceship to be constructed, and was created by Andrew J. Wade in 2010.[1][2] It displaces itself by 5,120 cells vertically and 1,024 cells horizontally every 33,699,586 generations, and is therefore an ibisship. It derives its name from the latin, gemini, meaning twins, describing its 2 identical halves, each of which contains three Chapman-Greene construction arms. A tape of gliders continually relays between the two halves, instructing each to delete its parent and construct a daughter configuration.

Gemini
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Pattern type	Spaceship
Number of cells	846278
Bounding box	4217807×4220191
Direction	Oblique
Slope	5
Period	33699586
Mod	33699586
Speed	(2560,512)c/16849793
Speed (unsimplified)	(5120,1024)c/33699586
Heat	Unknown
Discovered by	Andrew J. Wade
Year of discovery	2010
Rules Outer-totalistic rules B3/S23 only Important rules Conway Life # of rules 2^0 = 1
Glider synthesis Fewest gliders 173449 (32^†) Uploaded synthesis RLE gemini_synth.rle ^†Can be constructed with 32 gliders using the reverse caber tosser universal constructor.
Pattern files Macrocell gemini.mc Zip archive gemini.zip

It is the largest spaceship in terms of its diameter and bounding box, but has a much smaller population than the Caterpillar.

The pattern marks the thirteenth explicitly-constructed spaceship velocity, but facilitates an infinite range of related velocities. For example, Dave Greene has reduced its period by eight generations, whilst maintaining its displacement. Theoretically speaking, a Gemini-esque spaceship could be constructed with any velocity slower than (but not equal to) (1,1)c/580.[3] In June 2010, Greene also constructed slope-2 and slope-3 versions of the spaceship.[4][5]

Gemini was voted Pattern of the Year 2010 on the ConwayLife.com forums.[6]

Videos

<iframe src='//www.youtube.com/embed/X3wsFnwWK7E?' width='300' height='169' frameborder='0' allowfullscreen='true'></iframe> Various zoom levels of gemini demonstrating its size

<iframe src='//www.youtube.com/embed/A8B5MbHPlH0?' width='300' height='169' frameborder='0' allowfullscreen='true'></iframe> Some of Gemini's features (with CA music)

Pattern files

• Gemini
• Gemini 2
• Gemini 3

See also

• Geminoid
• Replicator
• Half-baked knightship

References

1. Adam P. Goucher (May 19, 2010). "Oblique Life spaceship created". Game of Life News. Retrieved on May 21, 2010.
2. Andrew J. Wade (May 18, 2010). Universal Constructor Based Spaceship (discussion thread) at the ConwayLife.com forums
3. Adam P. Goucher (May 21, 2010). "Universal Constructor Based Spaceship". Retrieved on May 21, 2010.
4. Dave Greene (June 13, 2010). Re: Shrinking Gemini: Four Ideas (discussion thread) at the ConwayLife.com forums
5. Dave Greene (June 14, 2010). Re: Shrinking Gemini: Four Ideas (discussion thread) at the ConwayLife.com forums
6. Adam P. Goucher (January 17, 2011). Re: Votes for Pattern of the Year 2010 (discussion thread) at the ConwayLife.com forums

External links

• Gemini at the Life Lexicon
• New Scientist: First replicating creature spawned in life simulator
• downloadable zip of the Gemini RLE file (Google is not allowing to download the file, but you can Share->Email as attachment to yourself)
• Gemini RLE file with programs used to construct it (on Google docs so download quota may be exceeded by the time you attempt download.)
• Gemini RLE file with programs used to construct it (alternate download on drop.io)