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x = 3, y = 3, rule = B3/S23 bo$obo$2o! #C [[ THUMBSIZE 2 THEME 6 GRID GRIDMAJOR 0 SUPPRESS THUMBLAUNCH ]] #C Still life
Pattern type Strict still life
Number of cells 5
Bounding box 3 × 3
Frequency class 2.8
Discovered by JHC group
Year of discovery 1970

The boat is the only still life with 5 cells, discovered by the JHC group in 1970.[1]

It can be thought of as a tub with an extra cell in one of the corners, or a ship with one of the corner cells removed. It can also be seen as a very deep siamization of two hooks.

Boat extensions

Perhaps the most notable property is that the boat begins an infinite series of still lifes which consist of two parallel diagonal lines being stabilised. The next still lifes in this line, the long boat, very long boat and so on, show that this allows for the construction of a still life with any odd number of cells equal to or greater than 5. It is possible to have spaceships and other such patterns arbitrarily extend the boat in this manner as a wickstretcher, referred to as a boatstretcher.

Uses in catalysis

The boat sees uses in, and can arise as a result of, certain interactions.

In the orientation shown in the infobox, moving the uppermost cell up one cell right turns it back into a boat in one generation. This property allows it to be used as a catalyst in certain situations, such as the p21 B-heptomino hassler, p22 lumps of muck hassler, p35 honey farm hassler, the still life form of diuresis, the sidesnagger reaction found in the p130 shuttle, one variant of the RF28B conduit, and more. See Tutorials/Catalyses for more examples.

Miscellaneous reactions

The boat can be hit by a glider to cleanly produce another glider, travelling perpendicular to the direction of the input glider. It is thus a one-time reflector.

A glider hitting certain still lifes in the correct way, such as a snake or eater 1, as well as oscillators such as the beacon if correctly timed, will produce a boat; another glider in the same lane will cleanly destroy the boat. This is called a boat-bit. This reaction can be used in a similar way to an eater which works on pairs of gliders.


Main article: List of common still lifes

Boat is the fourth most common still life on Adam P. Goucher's Catagolue, being less common than loaf but more common than ship. It is the only still life with 5 cells.[2] It is also the sixth most common object overall on Catagolue. The boat was also the fourth most common still life in Achim Flammenkamp's census, again being slightly less common than loaf. It was over four times as common as tub,[3] which was the next most common still life rather than ship; see the ship's page for an explanation.

Glider synthesis

There is a head-on 2-glider collision that produces a single boat pointing to the approaching direction of one of the gliders.

See also


  1. Dean Hickerson's oscillator stamp collection. Retrieved on June 18, 2009.
  2. Adam P. Goucher. "Statistics". Catagolue. Retrieved on August 24, 2022.
  3. Achim Flammenkamp (September 7, 2004). "Most seen natural occurring ash objects in Game of Life". Retrieved on January 15, 2009.

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