Eater 1

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Eater 1
x = 4, y = 4, rule = B3/S23 2o$obo$2bo$2b2o! #C [[ THUMBSIZE 2 THEME 6 GRID GRIDMAJOR 0 SUPPRESS THUMBLAUNCH ]] #C [[ THUMBSIZE 3 ZOOM 21 HEIGHT 400 SUPPRESS ]] #C [[ ZOOM 42 ]]
Pattern type Strict still life
Number of cells 7
Bounding box 4 × 4
Frequency class 11.0
Discovered by Bill Gosper
Year of discovery 1971

Eater 1 (or fishhook or simply eater) is a 7-cell still life and the smallest asymmetric still life,[1] observed independently by several Life enthusiasts in 1971. The name "fishhook", which is also used, was suggested by Clement A. Lessner III and William P. Webb.[2]

This still life comprises the normally unstable pre-block with a normally unstable tail attached. This pattern can also be seen as a trans version of the bookend.

Eating reactions

Main article: Eater 1 reaction
x = 102, y = 14, rule = B3/S23 bobo$4bo$o3bo77bo$4bo8b5o8b4o10bo9b2o9bo9bo9bobo$bo2bo7bo4bo7bo3bo8bob o9b2o9bo8bobo8bobo$2b3o12bo11bo9b2o9b2o9bo7bo2bo9b2o$6b2o4bo3bo2b2o4bo 2bo2b2o9b2o9b2o8b2o5b2o2b2o9b2o7b2o$bo4bobo5bo4bobo9bobo8bobo8bobo7bob o8bobo8bobo6bobo$obo5bo12bo11bo10bo10bo9bo10bo10bo8bo3bo$bo6b2o11b2o 10b2o9b2o9b2o8b2o9b2o9b2o7b2o2bo$99bo$99bo$99bo$100b2o! #C [[ THUMBSIZE 2 THEME 6 GRID GRIDMAJOR 0 SUPPRESS THUMBLAUNCH ]] #C [[ THUMBSIZE 2 ZOOM 10 WIDTH 1200 GPS 10 ]]
Some eater 1s about to eat several different objects
(click above to open LifeViewer)
RLE: here Plaintext: here

A fishhook's ability to eat various objects was discovered by Bill Gosper late in 1971, which made it the first discovered glider eater. It only takes four generations to recover from being hit by a glider, making it the fastest-recovering as well as the smallest. In addition to being able to eat gliders, it can also eat blinkers, lightweight spaceships, loaves, middleweight spaceships, pre-beehives, R-bees and many other patterns, as shown above. Due to its ability to change the evolution of nearby objects without being affected itself, it appears as a stabilizer at the corner of dozens of oscillators including buckaroo, p54 shuttle, pentoad, p47 pre-pulsar shuttle, snacker and p23 honey farm hassler, as well as many stable conduits like F171, Fx77, L112 and so on.

Sometimes eater 1 can be replaced by a period-3 oscillator, which can reduce the bounding box of a pattern at the expense of population.[3][4]

Pre-block is not the only catalytic site on a fishhook. Its tail can be used as a rock that eats an unnamed 7-cell polyplet; another example of this type of catalysis can be found at generation 74 of Fx153. Its tail and head can also trigger a boat-bit reaction, and in this manner it can be considered a G0 glider pair eater.

There are also unusual rare catalyses where the eater tail is temporarily destroyed by an active reaction and then restored back.[5][6]


See also: List of common still lifes

Eater 1 is the thirteenth most common still life on Adam P. Goucher's Catagolue, being less common than mango but more common than long barge. Among all still lifes with 7 cells, it is the third most common, being less common than long boat but more common than long snake.[7]It is also the seventeenth most common object overall on Catagolue, and the rarest object in Catagolue for which a 2-glider synthesis exists.

In Achim Flammenkamp's census, eater 1 was also ranked thirteenth most common, again between the mango and long barge.[8]

Glider synthesis

x = 65, y = 65, rule = B3/S23 62bo$62bobo$62b2o6$15bo$13b2o$14b2o3$18bo$17bo34bo$17b3o31bo$51b3o$6bo 29bo25b3o$5bobo27bobo9b3o12bo$7bo9b2o18bo9bo10bo4bo$7b2o7b2o19b2o9bo8b 2o$18bo38bobo2$22b3o36b2o$22bo37b2o$23bo38bo12$6bo29bo$5bobo27bobo$7bo 29bo$7b2o28b2o$b2o$obo$2bo$11bo$10b2o28bo$b2o7bobo26b2o$2b2o35bobo$bo$ 35b3o$37bo$11b3o22bo$11bo$12bo2$51b2o$50b2o$52bo5$56b2o$56bobo$56bo! #C [[ THUMBSIZE 2 THEME 6 GRID GRIDMAJOR 0 SUPPRESS THUMBLAUNCH ]] #C [[ ZOOM 8 HEIGHT 600 ]]
Common edge-shooting eater 1 recipes
(click above to open LifeViewer)
RLE: here Plaintext: here

There is a perpendicular 2-glider collision that produces an eater 1 and a domino spark, the latter of which is consumed in four more ticks.

Several ways to drop an eater 1 on the reaction envelope are known, for example a two-stage four-glider recipe involving an intermediate pond. These can be useful for constructing larger patterns with tight space and/or time restrictions.

In other rules

In the isotropic non-totalistic rules between B4a5q/S2aek and B2-ae34-n5678/S0123-nr45678, the eater is a diagonally glide-symmetric period-2 oscillator.

x = 4, y = 4, rule = B4a5q/S2aek 2o$bo$bobo$2b2o! #C [[ THUMBSIZE 2 THEME 6 GRID GRIDMAJOR 0 SUPPRESS THUMBLAUNCH ]] #C [[ AUTOSTART GPS 2 ]]
The oscillator form
(click above to open LifeViewer)

See also


  1. Dean Hickerson's oscillator stamp collection. Retrieved on March 14, 2020.
  2. Robert Wainwright (June 1971). Lifeline, vol 2, page 3.
  3. Arie Paap (April 6, 2018). Re: Execution of Old Guns by Variable-Speed Firing Squad (discussion thread) at the forums
  4. Matthias Merzenich (June 3, 2018). Re: Execution of Old Guns by Variable-Speed Firing Squad (discussion thread) at the forums
  5. simsim314 (May 8, 2015). Re: The Hunting of the New Herschel Conduits (discussion thread) at the forums
  6. gmc_nxtman (August 7, 2015). Re: Thread for your unsure discoveries (discussion thread) at the forums
  7. Adam P. Goucher. "Statistics". Catagolue. Retrieved on June 24, 2016.
  8. Achim Flammenkamp (September 7, 2004). "Most seen natural occurring ash objects in Game of Life". Retrieved on January 15, 2009.

External links