Switch engine
| Switch engine | |||||||
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| Pattern type | Methuselah | ||||||
|---|---|---|---|---|---|---|---|
| Number of cells | 8 | ||||||
| Bounding box | 6 × 4 | ||||||
| MCPS | 10 | ||||||
| Lifespan | 3911 generations | ||||||
| Final population | 842 | ||||||
| L/I | 488.9 | ||||||
| F/I | 105.3 | ||||||
| F/L | 0.215 | ||||||
| L/MCPS | 391.1 | ||||||
| Static symmetry | Unspecified | ||||||
| Discovered by | Charles Corderman | ||||||
| Year of discovery | 1971 | ||||||
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A switch engine (or Corder engine[1]) is a methuselah that was found by Charles Corderman in 1971.[2] It produces a copy of itself after 48 generations, glide-reflected 4 cells northwest (starting in the form to the right), along with some active junk. If left unattended, the accumulating exhaust overtakes and destroys the engine after 24 cycles, but it can be stabilized to make c/12 diagonal puffers and spaceships.
History
In 1971, Charles Corderman investigated the fate of all the small polyominoes exhaustively. Records indicate that he found the switch engine while investigating the decominoes (polyominoes having 10 cells). However, there do not appear to be[citation needed] decominoes which result in a clean switch engine. There is, on the other hand, a unique[citation needed] nonomino switch engine predecessor whose 2-tick descendant matches that of a switch engine:
| (click above to open LifeViewer) RLE: here Plaintext: here |
It is the smallest known polyomino to do so. If Corderman was examining polyominoes in order of size, then this smaller predecessor should have been found first in any case.
Stabilization
There are two basic types of stabilized switch engine, both of which were also found by Charles Corderman: the period 288 block-laying switch engine (the more common of the two) and period 384 glider-producing switch engine. These two puffers are the most natural infinite growth patterns in Conway's Game of Life, being by far the most common ones to occur from non-symmetric random starting patterns.[3] Switch engine-based puffers, and combinations thereof, are also the only infinite growth patterns observed to have emerged from asymmetric soups on Catagolue.
Because the switch engine lends itself so naturally to infinitely-growing patterns, it appears in many of the smallest known superlinear growth patterns, including the mosquitoes, catacryst, metacatacryst, Gotts dots, and 26-cell quadratic growth.
In addition to the puffers based on a single switch engine, puffers such as Noah's ark can be created by combining two switch engines. Such puffers are generally quite dirty. However, it is also possible to create Corderships made of switch engines that interact to remove their combined exhaust. These move at c/12 diagonally and are thus the slowest known spaceships in Life other than the adjustable ships. Such spaceships can be constructed by combining as few as two switch engines.
'Swimmer' tracks
- Main article: Switch engine channel
Like Herschels, switch engines can be supported by conduits made out of well-separated still lifes.[4] These 'swimmer tracks' were discovered by David Bell in 2005, and can be any length. Stable converters have been constructed that convert Herschels to switch engines and back[5]. Much faster, smaller and more efficient Herschel-to-swimmer converters can now be constructed with new technology, particularly Snark reflectors.[6]
Stable pattern
The stable pattern that results from the switch engine has 842 cells. It consists of 60 blocks, 33 beehives (including one honey farm), 50 blinkers (including eight traffic lights), 12 gliders, 11 boats, 11 loaves, four ships, two long boats, two ponds, and two tubs.
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Synthesis
In 1973, Douglas G. Petrie employed a 4-glider recipe of a switch engine in his synthesis for a block-laying switch engine.[7] Decades later, Luka Okanishi discovered a surprisingly small 3-glider synthesis for a clean switch engine on March 12, 2017.[8]
See also
References
- ↑ "Corder engine". The Life Lexicon. Stephen Silver. Retrieved on June 10, 2009.
- ↑ Robert Wainwright (December 1971). Lifeline, vol 4, page 2.
- ↑ "Census - Catagolue". Retrieved on September 28, 2015.
- ↑ Dave Greene (September 6, 2005). "Bobsled run update". Game of Life News. Retrieved on September 21, 2014.
- ↑ Dave Greene (June 17, 2007). "A New Kind of Signal". Work in Progress blog. Retrieved on September 21, 2014.
- ↑ Dave Greene (March 25, 2017). "Re: Implications of a Three-Glider Switch Engine". Retrieved on February 13, 2018.
- ↑ Robert Wainwright (June 1973). Lifeline, vol 10, page 5.
- ↑ Luka Okanishi (March 12, 2017). Re: Thread For Your Accidental Discoveries (discussion thread) at the ConwayLife.com forums
External links
- Switch engine at the Life Lexicon