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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.


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

Glider synthesis

A 12-glider synthesis was constructed the day following its occurrence by Tanner Jacobi.[3]

See also


  1. Eric Weisstein. "Quad". Eric Weisstein's Treasure Trove of Life. Retrieved on May 1, 2009.
  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

  • 16P2.19 at Heinrich Koenig's Game of Life Object Catalogs