Eater 3

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Eater 3
x = 12, y = 12, rule = B3/S23 9b2o$4b2o2bo2bo$bo2bo4bobo$obobo5bo$bo2bob2o$4bo2bo$5bo4bo$6b5o2$8bo$ 7bobo$8bo! #C [[ THUMBSIZE 2 THEME 6 GRID GRIDMAJOR 0 SUPPRESS THUMBLAUNCH ]] #C [[ THUMBSIZE 3 ZOOM 21 HEIGHT 400 SUPPRESS ]] #C [[ THUMBSIZE 2 ZOOM 26 ]]
Pattern type Quasi still life
Eater
Number of cells 31
Bounding box 12 × 12
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.

x = 20, y = 20, rule = B3/S23 11bo$10bobo$11bo2$9b5o$9bo4bo$12bo2bo$12b2obo2bo$9b2o4bobobo$4b2o2bo2b o3bo2bo$bo2bo4bobo2b2o$obobo5bo$bo2bob2o$4bob2o$5bo4bo$6b5o2$8bo$7bobo $8bo! #C [[ THUMBSIZE 2 THEME 6 GRID GRIDMAJOR 0 SUPPRESS THUMBLAUNCH ]] #C [[ THUMBSIZE 2 HEIGHT 400 ZOOM 18 GPS 3 AUTOSTART ]]
A related period-8 oscillator: 2 eater 3s share a loaf
(click above to open LifeViewer)
RLE: here Plaintext: here
Catagoluehere

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

On July 2, 2016, Mark Niemiec found an 18-glider synthesis based on a reaction found by Bullet51,[4] for an eater 3 variant (Catagoluehere) using buns as stabilizers. Before this the cheapest known construction recipe for any eater 3 variant needed 72 gliders. The next day, Chris Cain found a 14-glider synthesis of another variant (Catagoluehere) using bookends,[5] which was later reduced to 13 gliders at some point. In April 2020 GUYTU6J reduced the bun variant to 16 gliders.[6] On February 15, 2024, KtT reduced the cost of the bookend version to 12 gliders.[7][8]

Gallery

x = 11, y = 8, rule = B3/S23 7b2o$2b2o2bobo$2bo3bo$3b3ob4o$5bobo2bo$b3obobo$o2bob2o$2o! #C [[ THUMBSIZE 2 THEME 6 GRID GRIDMAJOR 0 SUPPRESS THUMBLAUNCH ]] #C [[ THUMBSIZE 2 ]]
A smaller variant of eater 3 with a drifter-type active reaction;[9][10] 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
x = 17, y = 17, rule = B3/S23 15bo$14bo$14b3o3$9b2o$4b2o2bo2bo$bo2bo4bobo$obobo5bo$bo2bob2o$4bo2bo$ 5bo4bo$6b5o2$8bo$7bobo$8bo! #C [[ THUMBSIZE 2 THEME 6 GRID GRIDMAJOR 0 SUPPRESS THUMBLAUNCH ]] #C [[ THUMBSIZE 2 ]]
Eater 3 eating a glider
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x = 22, y = 18, rule = B3/S23 bo$2bo$3o3$6bo$7bo$5b3o3$16b2o$11b2obo2bo2bo$10bobob2obobobo$7bo2bobo 4bo2bo$7b4ob4obo$11bo4bo$9bobo2bo$9b2o3b2o! #C [[ THUMBSIZE 2 THEME 6 GRID GRIDMAJOR 0 SUPPRESS THUMBLAUNCH ]] #C [[ THUMBSIZE 3 GPS 5 WIDTH 560 HEIGHT 600 ]]
Eater 3 variant that produces a thumb, allowing for engineered thumbs with periods 20 and above.
(click above to open LifeViewer)
Catagoluehere

See also

Notes

  1. Found by Nico Brown,[2] synthesised in 52 gliders by DroneBetter.[3]
  2. 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

  1. Dean Hickerson's oscillator stamp collection. Retrieved on March 14, 2020.
  2. Nico Brown (January 15, 2015). Re: Thread For Your Accidental Discoveries (discussion thread) at the ConwayLife.com forums
  3. DroneBetter (May 21, 2023). Re: Synthesising oscillators (discussion thread) at the ConwayLife.com forums
  4. Mark Niemiec (July 2, 2016). Re: Thread for your unsure discoveries (discussion thread) at the ConwayLife.com forums
  5. Chris Cain (July 3, 2016). Re: Thread for your unsure discoveries (discussion thread) at the ConwayLife.com forums
  6. GUYTU6J (April 12, 2020). Re: Synthesising Oscillators (discussion thread) at the ConwayLife.com forums
  7. KtT (February 15, 2024). Re: Still Life Synthesis Thread (discussion thread) at the ConwayLife.com forums
  8. shinjuku (#6176752120) (February 15, 2024). Job triggered by Adam P. Goucher at GitLab Catagolue project.
  9. Matthias Merzenich (November 18, 2021). Re: Execution of Old Guns by Variable-Speed Firing Squad (discussion thread) at the ConwayLife.com forums
  10. Dave Greene (January 9, 2022). Re: Thread for basic questions (discussion thread) at the ConwayLife.com forums

External links