Eater 3
| Eater 3 | |||||||||||
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| Pattern type | Eater | ||||||||||
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| Number of cells | 31 | ||||||||||
| Bounding box | 12 × 12 | ||||||||||
| Static symmetry | D2_x | ||||||||||
| Discovered by | David Buckingham | ||||||||||
| Year of discovery | 1977 | ||||||||||
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Eater 3 is a large symmetric eater that was found by David Buckingham on June 22, 1977.[1] It has a very different eating reaction from eater 1 and eater 2; however, it shares with those two eaters the ability to eat gliders. The loaf can take bites out of things, being flipped over in the process. The rest of the object, which is a 24-cell semi-natural strict still life (xs24_xo81v04a4z3iai21zw1), simply flips it back again with the central pre-block.
The eater 3 can be reduced in bounding box area by using snakes rather than tubs in the casing; this property can be used to compact many patterns where eater 3 appears near the edge, such as the rectifier, bronco, smallest known period-61 glider gun, Lx65 and Rx202.
Use in oscillators
Two copies of the eater 3 can share a loaf, forming the period-8 oscillator shown below.
| A related period-8 oscillator: 2 eater 3s share a loaf (click above to open LifeViewer) RLE: here Plaintext: here Catagolue: here |
Eater 3 is used in many oscillators including sailboat, 120P34, p42 glider shuttle and p50 glider shuttle. In particular, there are examples that have a corresponding polymer form with loaves being flipped back and forth by off-phase copies, for which eater 3 provides monomerisations.
| Monomer | Polymer |
|---|---|
| unnamed p8 | tetramer[n 1] |
| Grid's p16 variant | tetramer |
| queen bee shuttle | ouroboros bees-like tetramer |
| 90º queen bee shuttle pair | antiphase and synchronised dimers[n 2] |
| p88 pi and block hassler | tetramer |
Glider synthesis
Before 2016, the cheapest known construction recipe for any eater 3 variant needed 72 gliders.
On July 2, 2016, Mark Niemiec found an 18-glider synthesis based on a reaction found by Bullet51,[4] for an eater 3 variant (Catagolue: here) using buns as stabilizers. In April 2020 GUYTU6J reduced the bun variant to 16 gliders.[5] On October 7, 2024, an exhaustive search by Alex Greason using QuSrc for 5-glider syntheses in 15 × 15 bounding boxes, recording reductions for objects with Shinjuku entries reduced the initial component (a block-and-two-boats constellation) from 6 to 5 gliders, reducing the bun variant to 15 gliders.[6]
On July 3, 2016, Chris Cain found a 14-glider synthesis of another variant (Catagolue: here) using bookends,[7] which was later reduced to 13 gliders at some point. On February 15, 2024, KtT reduced the bookend version to 12 gliders.[8][9]
In other rules
When the S5r survival transition is added, eater 3 can be greatly reduced to a rock canoe and loaf that, in total, has 15 cells. In the rule B3/S235r, this allows for sailboat, 120P34 and p52 R-pentomino hassler to be reduced this way. [10]
| Canoe variant and normal eater 3 share a loaf in the rule B3/S235r, creating a period-8 oscillator. (click above to open LifeViewer) Catagolue: here |
Gallery
| A smaller variant of eater 3 with a drifter-type active reaction;[11][12] can be used e.g. in p71 honey farm hassler, odd traffic stop, speed tunnel variant and a toggle circuit. While it is smaller than the standard form in both population and bounding box, it has a much lower clearance. (click above to open LifeViewer) RLE: here Plaintext: here Catagolue: here |
| Eater 3 eating a glider (click above to open LifeViewer) |
| Eater 3 variant that produces a thumb, allowing for engineered thumbs with periods 20 and above. (click above to open LifeViewer) Catagolue: here |
See also
Notes
- ↑ Found by Nico Brown,[2] synthesised in 52 gliders by DroneBetter.[3]
- ↑ The synchronised one has two loaves perturbing and reflecting from each other, a reaction specific to this oscillator, of those shown here (due to the loaf being perturbed into 2bo$bobo$o$bo! instead of 2b2o$bo$o$o!)
References
- ↑ Dean Hickerson's oscillator stamp collection. Retrieved on March 14, 2020.
- ↑ Nico Brown (January 15, 2015). Re: Thread For Your Accidental Discoveries (discussion thread) at the ConwayLife.com forums
- ↑ DroneBetter (May 21, 2023). Re: Synthesising oscillators (discussion thread) at the ConwayLife.com forums
- ↑ Mark Niemiec (July 2, 2016). Re: Thread for your unsure discoveries (discussion thread) at the ConwayLife.com forums
- ↑ GUYTU6J (April 12, 2020). Re: Synthesising Oscillators (discussion thread) at the ConwayLife.com forums
- ↑ Adam P. Goucher, on behalf of Catagolue synthesis box submitters. contrib_20241007.sjk on Shinjuku
- ↑ Chris Cain (July 3, 2016). Re: Thread for your unsure discoveries (discussion thread) at the ConwayLife.com forums
- ↑ KtT (February 15, 2024). Re: Still Life Synthesis Thread (discussion thread) at the ConwayLife.com forums
- ↑ shinjuku (#6176752120) (February 15, 2024). Job triggered by Adam P. Goucher at GitLab Catagolue project.
- ↑ Haycat Durnak (March 27, 2024). Re:Oscillator Discussion Thread (1-transition) (discussion thread) at the ConwayLife.com forums
- ↑ Matthias Merzenich (November 18, 2021). Re: Execution of Old Guns by Variable-Speed Firing Squad (discussion thread) at the ConwayLife.com forums
- ↑ Dave Greene (January 9, 2022). Re: Thread for basic questions (discussion thread) at the ConwayLife.com forums
External links
- Eater 3 at the Life Lexicon
- 18 easily-constructible constellations 26 bits and larger at Mark D. Niemiec's Life Page
- Eater 3 at Adam P. Goucher's Catagolue (pseudo-object)
- Eater 3 minus loaf at Adam P. Goucher's Catagolue
- Eater 3 with trans-bookends at Adam P. Goucher's Catagolue (cheapest known variant)
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