Difference between revisions of "B-heptomino"
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Revision as of 17:58, 6 March 2019
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|Discovered by||John Conway|
|Year of discovery||1970|
The B-heptomino (or B-heptaplet, if the top-left cell is shifted one cell left) is a very common methuselah that evolves into three blocks, two gliders and a ship after 148 generations. Compare with Herschel, which appears at generation 20 of the B-heptomino's evolution. B-heptominoes acquired particular importance in 1996 due to David Buckingham's work on B tracks.
This pattern often arises with the cell at top left shifted one space to the left, producing a seven-bit polyplet that shares the same eight-bit descendant but is not technically a heptomino at all. This alternate form is shown as the input for elementary converter patterns such as BFx59H and BRx46B. Many conduits produce this form of B, so it can be used when marking the position of an output B-heptaplet.
The B-heptomino is considered a failed puffer or failed spaceship, since on its own it travels at c/2 for only a short time before being affected by its own trailing debris. However, it can be stabilized into a c/2 puffer or into a clean c/2 rake or spaceship. See, e.g., puffer 2, backrake 2, ecologist, or pufferfish.
In other rules
The B-heptomino is a stable puffer in many rules.
- In B3/S23-e4e, it evolves into a (16,5)c/74 oblique spaceship.
- In B3/S23-a, it is a glide-symmetric 10c/20 spaceship.
- In B34ej5y6n/S23, it is an oblique quadratic replicator, one of only a few known.
- In B36n/S2-i36c7c, it evolves into a glide-symmetric 9c/70 diagonal spaceship.