|View static image|
|Number of cells||134|
|Discovered by||David Bell|
|Year of discovery||2005|
The 4-engine Cordership is a c/12 diagonal spaceship that was discovered by David Bell on July 9, 2005. It is composed of four switch engines. It is the second smallest known Cordership in terms of its minimum population of 134 cells, superseded by the 2-engine Cordership. David Bell used this spaceship to create a small sawtooth, sawtooth 260.
An analysis of this Cordership reveals that the inner two and outer two switch engines have some degree of temporal independence from each other. The reason is that the inner exhaust from the outer engines create a block that is then hit by the inner engines' outer exhaust, making a blinker that then gets hit with the outer engines' outer exhaust (as well as a block from the outer engines' outer exhaust) to create another block-this is then destroyed by the outer exhaust from the outer switch engines. Each new object only needs to form in time to get converted into the next object/nothing, and this allows for variability in timing. In addition, there is also a small degree of spatial independence. The inner engines' inner exhaust cancel out via the same interaction as in switchwave, said exhaust still cancels out if the halves are put one cell farther away from each other than usual. As a result, there are many variations of this Cordership.
A slight modification of this Cordership that is asymmetric, with a minimum population of 136 cells, is also quite well-known and displayed below.
In November 2014 Michael Simkin discovered an alternate 4-engine Cordership, with temporally independent front and back halves -- the last two switch engines can be delayed by any number of ticks relative to the front. The front and back halves of the Cordership can be produced by identical glider constructions. These features were used to construct the infinite Corderships gun.
|Two versions of Michael Simkin's extensible 4-engine Cordership|
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RLE: here Plaintext: here
- Jason Summers' jslife pattern collection. Retrieved on October 28, 2020.
- Dave Greene (August 10, 2005). "New Sawtooth Patterns". Retrieved on April 21, 2017.
- Michael Simkin (November 5, 2014). "Four engine extendable Cordership". Retrieved on April 21, 2017.
- Adam P. Goucher (January 22, 2018). "Re: Stable signal converters". Retrieved on September 15, 201.