Tub

Tub
x = 3, y = 3, rule = B3/S23 bo$obo$bo! #C [[ THUMBSIZE 2 THEME 6 GRID GRIDMAJOR 0 SUPPRESS THUMBLAUNCH ]] #C Still life
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Pattern type	Strict still life
Number of cells	4
Bounding box	3×3
Frequency class	5.0
Discovered by	JHC group
Year of discovery	1970
Rules Outer-totalistic rules B/S2 – B35678/S012345678 Important rules Conway Life, HighLife # of rules 213 = 8192 Isotropic rules B/S2c – B2-e34-e5678/S012345678
Glider synthesis Fewest gliders 3 Catagolue-generated RLE tub_synth.rle Uploaded synthesis RLE tub_synth.rle
Pattern files Plaintext tub.cells RLE tub.rle
Identifiers apgcode xs4_252 Pentadecathlon ID 4.2

The tub is one of only two 4-cell still lifes (the other being the block) and was discovered by the JHC group in 1970.

Adding an extra cell to one of the corners results in a boat, while adding two to opposite corners results in a ship. It can also be seen as a long^-1 version of the barge.

Behaviour

Two mechanisms for a tub acting as an eater are known, though rarely applicable. An example of the former is the Eureka shuttle. The other mechanism involves the tub acting as a rock; an example is 5blink. This can be generalized to a large number of still lifes including a tub-like protrusion (e.g. boat, loaf, cis-hook with tail).

The tub is also occasionally useful as a simple induction coil for a row of 5 cells: see e.g. airforce.

Commonness

The tub is the fifth most common still life in Achim Flammenkamp's census, being about a quarter as common as the boat but only slightly more common than the pond. It is also the eighth most common object (and the less frequent of the two 4-bit still lifes) on Adam P. Goucher's Catagolue.

See also

• Tub with tail

External links

• Tub at the Life Lexicon

• Tub at Adam P. Goucher's Catagolue
• The 2 four-bit still-lifes at Mark D. Niemiec's Life Page