B-heptomino
| B-heptomino | |||||||||
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| Pattern type | Methuselah | ||||||||
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| Number of cells | 7 | ||||||||
| Bounding box | 4 × 3 | ||||||||
| MCPS | 7 | ||||||||
| Lifespan | 148 generations | ||||||||
| Final population | 28 | ||||||||
| L/I | 21.1 | ||||||||
| F/I | 4 | ||||||||
| F/L | 0.189 | ||||||||
| L/MCPS | 21.1 | ||||||||
| Static symmetry | C1 | ||||||||
| Discovered by | John Conway | ||||||||
| Year of discovery | 1970 | ||||||||
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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. Many conduits produce this form of B via the R-pentomino, so these two forms of B can be used interchangeably when marking in conduits.
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 with escorts or a suitable backend. See, e.g., puffer 2, backrake 2, ecologist, or pufferfish. The B-heptaplet can also serve as a tagalong moving at 2c/5, for spaceships with a sufficiently isolated dot spark.
In other rules
The B-heptomino is a stable puffer, spaceship, replicator, or oscillator in many non-totalistic rules. For example:
- 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.
- In B34t5y7/S23, it is a c/2 spaceship.
Gallery
A 6-cell parent
Generation 20, showing Herschel offspring
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| Generation 148 |
See also
- B-heptomino hasslers
- Herschel
- C-heptomino
- Conduit 1
- Lifeline Volume 1
- Omniperiodic
- Transparent block reaction
External links
- B-heptomino at the Life Lexicon
- Period 16284 Agar at Game of Life News. Posted by Heinrich Koenig on July 15, 2006.
- "Single B Heptomino". Game of Life Information, Class 4 Objects Catalog, Type B -- Puffer Trains.
- "Twin B Heptomino". Game of Life Information, Class 4 Objects Catalog, Type B -- Puffer Trains.