Eater/block frob

Eater/block frob
x = 10, y = 10, rule = B3/S23 b2o$2bo$2bobo$3bobo$5b2ob2o$8b2o$2b2o$3bo$3o$o! #C [[ THUMBSIZE 2 THEME 6 GRID GRIDMAJOR 0 SUPPRESS THUMBLAUNCH ]] #C [[ AUTOSTART ]] #C [[ HEIGHT 500 THUMBSIZE 3 ZOOM 36 GPS 2 LOOP 4 ]]
View animated image
View static image
Pattern type	Oscillator
Number of cells	20
Bounding box	10 × 10
Period	4
Mod	4
Heat	8.5
Volatility	0.55
Strict volatility	0.55
Discovered by	David Buckingham
Year of discovery	Unknown
Rules Outer-totalistic rules B3/S23 – B3678/S023678 # of rules 27 = 128 Isotropic rules B3-ceky/S2-n3-ejky – B2i34-ajnr5-acq678/S0234-ajnrw5-ijq678
Glider synthesis Fewest gliders 8 Catagolue-generated RLE synthesis Uploaded synthesis RLE eaterblockfrob_synth.rle
Pattern files Plaintext eaterblockfrob.cells RLE eaterblockfrob.rle
Identifiers apgcode xp4_64k8wc871zx1ro Pentadecathlon ID 20P4.4

Eater/block frob is a period-4 oscillator found by David Buckingham in 1976 or earlier. Composed of an eater 1, a block, and what is roughly a melusine, it is essentially a tub-with-tail eater constantly being hassled. "Frob" is used by MIT as a generic term meaning "thing".

The block can be replaced with a long hook with tail, and the eater 1 can be replaced with an eater bridge eater or an emulator.

Its grin makes it useful in the p4 bumper.

Carson Cheng found an 11-glider synthesis of this oscillator on June 30, 2022. This was reduced to an 8-glider synthesis in August 2023 by MathAndCode, based on a 6-glider component that converts an eater 1 into this oscillator.

Occurrence and variants

This oscillator first appeared naturally on April 3, 2022, in a soup found by Charity Engine using apgsearch, though a seminatural C4_1 tetramerisation occurred on March 4, 2022, 30 days earlier, in which each quadrant's eater head is fused to the roughly-melusine to form a roughly-fuse with tail and nine. The reduction of the 5 cells in the eater body and melusine tail seems to make it easier to find than the monomer, despite each quadrant having to occur at a fixed displacement from the centre. On May 17, 2022, Charity Engine also found a D8_1 oscillator, that contains the frob's rotor in each of its octants, with the roughly-melusine's eater tail's stabilisation fulfilled by gutter preservation, and has 4.5 fewer cells per octant than the monomer.

x = 16, y = 16, rule = B3/S23 oobbbboobbboboob$ obbobbbbboboobbo$ oobboooboboboboo$ oobbbbooobbbbbbb$ oboobbobobobbbbo$ oobobboobbbbbobo$ bobobobooboboooo$ oooboobobbbooobb$ bbobobbbbobbboob$ ooboooobbobobobo$ obobbboobbbbobbo$ booooobboobboooo$ bbbbbobbooobboob$ oboobbbbobobbbbb$ obobbboobbbooboo$ bbbobbobobbobooo! #C [[ THUMBSIZE 2 THEME 6 GRID GRIDMAJOR 0 SUPPRESS THUMBLAUNCH ]] #C [[ THUMBSIZE 3 HEIGHT 585 ZOOM 12 GPS 2 ]]

(click above to open LifeViewer)

x = 31, y = 31, rule = B3/S23 ooobbbobbooooooooobobboobbboooo$ oboboooobobbboobboboooboobbbobo$ ooooobobbbobboooboobbbboboobooo$ obbbboobobobbbooobooooobooobobb$ bbooobboboobboobbbbooooobboboob$ bboobbbobbooboboooobbbooobbobob$ bobobooobbbooooobboobbboobboooo$ ooobooobbbbbooooobbbooobooobbob$ obboooboobooobbobboobbobbbbobbb$ boboobbobbobbbobbobbbbbbbbobboo$ boboobbobbobobobobooooobboooobo$ ooboobobobobobooboobbboboobbbbo$ bbooboobobooobooooooobooobbbbbo$ ooobbobbboboobbobbbbbbboooobooo$ obbobobobbobobooobooooboobooooo$ obooboooobbooooooooobbooooboobo$ ooooobooboooobooobobobbobobobbo$ oooboooobbbbbbbobboobobbbobbooo$ obbbbbooobooooooobooobobooboobb$ obbbboobobbbooboobobobobobooboo$ oboooobbooooobobobobobbobboobob$ oobbobbbbbbbbobbobbbobbobboobob$ bbbobbbbobboobbobboooboobooobbo$ bobbooobooobbbooooobbbbbooobooo$ oooobboobbboobbooooobbbooobobob$ bobobbooobbbooooboboobbobbboobb$ boobobbooooobbbboobboobobbooobb$ bbobooobooooobooobbboboboobbbbo$ oooboobobbbboobooobbobbbobooooo$ obobbboobooobobboobbboboooobobo$ oooobbboobbobooooooooobbobbbooo! #C [[ THUMBSIZE 2 THEME 6 GRID GRIDMAJOR 0 SUPPRESS THUMBLAUNCH ]] #C [[ THUMBSIZE 3 HEIGHT 585 ZOOM 12 GPS 2 ]]

(click above to open LifeViewer) Catagolue: here

x = 31, y = 31, rule = B3/S23 boobobobbboobobbboboobbboboboob$ obooobbbbbobooobooobobbbbbooobo$ ooboobobobbbobooobobbbobobooboo$ booboooooooobbbobbbooooooooboob$ oooooobobobbbobbbobbboboboooooo$ bbboobbbobobbobobobbobobbboobbb$ oboobboobobboobbboobboboobboobo$ bbbooboobbbbbbbobbbbbbbooboobbb$ bboobobbbobobooooobobobbboboobb$ bbbooboboboboooooooboboboboobbb$ oobobobbbooboobbbooboobbboboboo$ obbobbbbobbobobobobobbobbbbobbo$ boobbbobboobobbobboboobbobbboob$ oobboooboooobobbboboooobooobboo$ boobbbbboobbbbbobbbbboobbbbboob$ bbooboboooboobooobooboooboboobb$ boobbbbboobbbbbobbbbboobbbbboob$ oobboooboooobobbboboooobooobboo$ boobbbobboobobbobboboobbobbboob$ obbobbbbobbobobobobobbobbbbobbo$ oobobobbbooboobbbooboobbboboboo$ bbbooboboboboooooooboboboboobbb$ bboobobbbobobooooobobobbboboobb$ bbbooboobbbbbbbobbbbbbbooboobbb$ oboobboobobboobbboobboboobboobo$ bbboobbbobobbobobobbobobbboobbb$ oooooobobobbbobbbobbboboboooooo$ booboooooooobbbobbbooooooooboob$ ooboobobobbbobooobobbbobobooboo$ obooobbbbbobooobooobobbbbbooobo$ boobobobbboobobbboboobbboboboob! #C [[ THUMBSIZE 2 THEME 6 GRID GRIDMAJOR 0 SUPPRESS THUMBLAUNCH ]] #C [[ THUMBSIZE 3 HEIGHT 585 ZOOM 12 GPS 2 ]]

(click above to open LifeViewer) Catagolue: here

A similar replacement of the roughly-melusine to that in the D8_1 variant above can be achieved with a dimer with a tub. Two eater/block frobs can also hassle a beacon (that replaces the block for each), in either a cis- or trans- configuration, from which another D8_1 variant has also occurred seminaturally, with the eaters on the outside.

See also

• Confused eaters
• Two eaters
• Hooks

External links

• Eater/block frob at the Life Lexicon
• Eater/block frob at Adam P. Goucher's Catagolue
• The 23 twenty-bit period 4 oscillators at Mark D. Niemiec's Life Page (download pattern file: 20/20eebf.rle)
• 20P4.4 at Heinrich Koenig's Game of Life Object Catalogs
• Eater/long hook with tail frob at Adam P. Goucher's Catagolue
• Eater bridge eater/block frob at Adam P. Goucher's Catagolue