Eater 1

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 ]]
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Pattern type	Strict still life Eater
Number of cells	7
Bounding box	4 × 4
Frequency class	11.0
Static symmetry	n (C1)
Discovered by	Bill Gosper
Year of discovery	1971
Rules Outer-totalistic rules B/S23 – B3678/S012345678 # of rules 211 = 2048 Isotropic rules B/S2aek3nr – B2-ae34-an5-q678/S012345678
Glider synthesis Fewest gliders 2 Catagolue-generated RLE synthesis Uploaded synthesis RLE eater1_synth.rle
Pattern files Plaintext eater1.cells RLE eater1.rle
Identifiers apgcode xs7_178c Niemiec ID 7et Pentadecathlon ID 7.3

Eater 1 (or fishhook or simply eater) is a 7-cell still life and the smallest asymmetric still life, 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. It is an eater that can eat various objects.

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. Replacing the tail with long tail yields shillelagh.

Eating reactions

Main article: Eater 1 reaction

x = 80, y = 32, rule = B3/S23 bo$obo16b2obo2b2o$2b2o16b2o2bo2bo9bobo$o23bobo9bo$o3bo20bo10bo3bo6bo$ 4bo2bo11bo16bo8bo3bo8bo2bo11bo$4o2bobo10b3o14bo2bo10bo11bo8bobo$6bo2b o12bo13b3o6bo4bo7bo3bo9b2o$4o2bobo12bo24b5o8b4o$4bo2bo6b2o3b2o6b2o11b 2o11b2o10b2o9b2o$o3bo9bobo10bobo5bo4bobo10bobo9bobo8bobo$o15bo12bo4bo bo5bo12bo11bo10bo$2b2o12b2o11b2o4bo6b2o11b2o10b2o9b2o$obo$bo6$50bo$11b 2o12bo11bo11bobo$11b2o12bo10bobo10bobo$11b2o12bo9bo2bo11b2o$14b2o11b2o 7b2o2b2o11b2o10b2o$14bobo10bobo10bobo10bobo9bobo$16bo12bo12bo12bo11bo 3bo$16b2o11b2o11b2o11b2o10b2o2bo$70bo$70bo$70bo$71b2o! #C [[ THUMBSIZE 2 THEME 6 GRID GRIDMAJOR 0 SUPPRESS THUMBLAUNCH ]] #C [[ THUMBSIZE 2 ZOOM 8 WIDTH 1000 GPS 10 ]]

Some eater 1s about to eat several different objects. Top (Ships, Left to Right): Dart, Loafer, MWSS (two, one with additional tub), LWSS, Glider. Bottom (Left to Right): Pre-beehive, Blinker, Loaf, Bun/R-bee, unnamed block predecessor. (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.

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.

Occurrence

See also: List of common still lifes, Most common objects on Catagolue

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. 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.

Glider synthesis

Main article: 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

• Eater 2, Eater 3, Eater 4, Eater 5
• List of common catalysts
• Tutorials/Catalyses for several uses and replacements of an eater 1.

External links

• Eater 1 at the Life Lexicon
• Eater 1 at Adam P. Goucher's Catagolue
• The 4 seven-bit still-lifes at Mark D. Niemiec's Life Page (download pattern file: 0/7et.rle)
• Eater at Heinrich Koenig's Game of Life Object Catalogs