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2o2b2o$obo2bo$4bo$bo$o2bobo$2o2b2o! #C [[ THUMBSIZE 2 THEME 6 GRID GRIDMAJOR 0 SUPPRESS THUMBLAUNCH ]] #C [[ AUTOSTART ]] #C [[ LOOP 2 GPS 2 THUMBSIZE 2 ]]
Pattern type Oscillator
Oscillator type Muttering moat
Family Barberpole
Number of cells 16
Bounding box 6 × 6
Period 2
Mod 1
Heat 8
Volatility 0.40
Strict volatility 0.40
Rotor type Clock
Discovered by Robert Kraus
Year of discovery 1971

Quad (or barberpole intersection[1]) is a period-2 oscillator and muttering moat that was found in April 1971 by Robert Kraus.[2] It has the same rotor as the clock. It and mold are the only flippers that fit inside a 6 × 6 bounding box; however, mold is period 4.

This oscillator first occurred naturally on December 28, 2015, in a soup submitted to Catagolue by Adam P. Goucher. A 12-glider synthesis was constructed the day following its occurrence by Tanner Jacobi.[3]

Information on this oscillator's natural occurrence with respect to other naturally-occurring patterns is currently unknown.


Despite having fourfold symmetry, quads typically form via twofold symmetry only. As shown below, there are two lumps of muck in the center, and the two outside objects shown can be anything with the same front two rows that does not interfere later.

x = 19, y = 6, rule = B3/S23 9b3o$bo7bo2b2o$3ob3o2b2o2bo3bo$4bo2b2o2b3ob2obo$4b2o2bo7bobo$6b3o8bo! #C [[ THUMBSIZE 2 THEME 6 GRID GRIDMAJOR 0 SUPPRESS THUMBLAUNCH ]] #C [[ GPS 4 THUMBSIZE 2 ]]
Quad predecessor
(click above to open LifeViewer)
RLE: here Plaintext: here

See also


  1. Conway's Life Glossary at Paul Callahan's Page of Conway's Life Miscellany
  2. Dean Hickerson's oscillator stamp collection. Retrieved on March 14, 2020.
  3. Tanner Jacobi (December 29, 2015). Re: Soup search results (discussion thread) at the ConwayLife.com forums

External links