The 4-engine Cordership is a diagonal c/12 spaceship that was discovered by David Bell on July 9, 2005. It is the second smallest known Cordership in terms of its minimum population of 134 cells, superseded by the 2-engine Cordership.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.
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 136-cell variant of the 4-engine Cordership.RLE: here
- ↑ 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.