3-glider collision
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A 3-glider collision is a collision of three gliders. There are infinitely many distinct 3-glider collisions as some 2-glider collisions generate output gliders, making it possible for another glider to collide with the output glider to form an arbitrarily faraway object or constellation.
In late 2017, an enumeration of 3G collisions was done by 2718281828, resulting in a database containing 464,746 entries.[note 1] Multiple scripts exist to search through the database to find 3-glider syntheses of stable constellations and unstable patterns.[note 2]
The following single objects have known 3-glider syntheses:
- 11 still lifes: paperclip, half-bakery, bi-pond, tub, barge, ship, long boat, long barge, mango, very long boat, hat
- 4 oscillators: beacon, toad, pulsar, pentadecathlon
- 3 spaceships: middleweight spaceship, heavyweight spaceship, lightweight spaceship
Trivia
The 3-glider synthesis of the pentadecathlon took until 1997 to be found, and of a clean switch engine took until 2017. It is unknown how many distinct evolution sequences from 3-glider collisions are possible, excluding infinite families of constellations, or whether any syntheses remain unknown.
Notes
- ↑ The data can be found in this forum post. Obtaining an exact count of "essentially different" 3G collisions is complicated by a number of factors, such as existence of glider-producing 2G collisions and Heisenburp-type reactions, and the difference between counting distinct reactions and counting distinct outputs.
- ↑ For the use of these scripts, please see the tutorial section of the 3-glider database; see also octo3g database.
See also
- 2-glider collision, 4-glider collision
- Patterns that can be constructed with 3 gliders (category)
- Ternary reaction
- Tee
External links
- Enumerating Three-Glider Collisions (discussion thread) at the ConwayLife.com forums
- glider-collisions code repository by Dave Greene (contains collision database and search scripts)
- Life Objects Buildable With 3 Gliders at Mark D. Niemiec's Life Page