Eater/block frob

	Eater/block frob
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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 (canonical)	10
Catagolue-generated RLE (canonical)	synthesis
Fewest gliders (cheapest variant)	8
Catagolue-generated RLE (cheapest variant)	synthesis
Uploaded synthesis RLE	eaterblockfrob_synth.rle
Pattern files
Plaintext	eaterblockfrob.cells
RLE	eaterblockfrob.rle
Identifiers
apgcode (canonical)	xp4_64k8wc871zx1ro
apgcode (cheapest variant)	xp4_178cw8k453zy0or1
Pentadecathlon ID	20P4.4

Eater/block frob is a period-4 oscillator found by David Buckingham in 1976 or earlier.^[1] 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".^[2]

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.

This oscillator first appeared naturally on April 3, 2022, in a soup found by Charity Engine using apgsearch.^[3]

Carson Cheng found an 11-glider synthesis of this oscillator on June 30, 2022,^[4] which was reduced to 10 gliders by Tanner Jacobi later the same day.^[5]

References

↑ Dean Hickerson's oscillator stamp collection. Retrieved on March 14, 2020.
↑ Mark Niemiec (November 27, 2016). Re: Help with names (discussion thread) at the ConwayLife.com forums
↑ Ian07 (April 3, 2022). Re: Soup search results (discussion thread) at the ConwayLife.com forums
↑ Carson Cheng (June 28, 2022). Re: Synthesising Oscillators (discussion thread) at the ConwayLife.com forums
↑ Tanner Jacobi (June 30, 2022). Message in #cgol on the Conwaylife Lounge Discord server