|View static image|
|Number of cells||132945|
|Discovered by|| Chris Cain|
|Year of discovery||2014|
Parallel half-baked knightship or Parallel HBK is a knightship based on the well-known half-bakery reaction with a glider, and an improvement over the original half-baked knightship. The design was proposed before the first half-baked knightship appeared on the scene, although the actual construction was completed several days later by Chris Cain. This design allows for several slow-salvo construction recipes to be completed in parallel, whereas the first half-baked knightship did all constructions serially.
There are several significant differences in design between the original half-baked knightship and Chris Cain's smaller version. The slow-salvo constructions are done serially in Goucher's design, and an extra glider is used to suppress the salvo that triggers the half-bakery trails.
Consequently, Cain's parallel knightship is much smaller than Goucher's original knightship, in terms of the population count, bounding box and period. It had also been the smallest known example of an oblique spaceship in Conway's Game of Life in terms of the bounding box before the discovery of the waterbear later in the same year. Finally, it had been the smallest true knightship (travelling on slope 2) in terms of cell count, until the discovery of Sir Robin in March 2018.
On December 31, 2014 Michael Simkin found a glider synthesis and allegedly built a gun for this spaceship, but nobody managed to run the Golly script that assembles the gun until the end. Subsequently, in June 2019, an anonymous user of the coding community repl.it modified Simkin's script to work in lifelib instead of Golly, completing in a mere 15 minutes. The result has exactly 873,324,548 cells in a bounding box of 287,594,511 by 172,045,883.