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x = 3, y = 3, rule = B3/S23 bo$obo$bo! #C [[ THUMBSIZE 2 THEME 6 GRID GRIDMAJOR 0 SUPPRESS THUMBLAUNCH ]] #C Still life
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

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.[1]

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.


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.


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.[2] 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.[3]

See also


  1. Dean Hickerson's oscillator stamp collection. Retrieved on June 18, 2009.
  2. Achim Flammenkamp (September 7, 2004). "Most seen natural occurring ash objects in Game of Life". Retrieved on January 15, 2009.
  3. Adam P. Goucher. "Statistics". Catagolue. Retrieved on June 24, 2016.

External links

No corners (barges) (^-2) • (^-1) • ^0^1^2^3
One corner (boats) (^-2) • (^-1) • ^0^1^2^3
Two corners (ships) (^-1) • ^0^1^2^3