Fore and back

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Fore and back
2ob2o2b$2obobob$6bo$3ob3o$o6b$bobob2o$2b2ob2o! #C [[ THUMBSIZE 2 THEME 6 GRID GRIDMAJOR 0 SUPPRESS THUMBLAUNCH ]] #C [[ AUTOSTART ]] #C [[ GPS 2 THUMBSIZE 2 ]]
Pattern type Oscillator
Oscillator type Billiard table
Number of cells 24
Bounding box 7×7
Frequency class 30.6
Period 2
Mod 1
Heat 4
Volatility 0.15
Strict volatility 0.15
Rotor type Pole 2
Discovered by Achim Flammenkamp
Year of discovery 1994

Fore and back (or complementary blinker [1]) is a period 2 oscillator that was found by Achim Flammenkamp in July 1994. Its rotor is the same as the blinker.


Fore and back is about the thirty-eighth most common naturally-occurring oscillator in Achim Flammenkamp's census, being less common than boat on spark coil and block on griddle, about as common as 21P2, and more common than trans-block on long hook eating tub and trans-beacon down on long hook.[2] It is the most common billiard table oscillator.


In August, 2013 a 24-glider synthesis of this oscillator was found by Martin Grant, based on a soup, provided by Lewis Patterson. Several days later Mark Niemiec improved this result, having found a 20-glider synthesis.[3]

In October 2014, Tanner Jacobi found a predecessor for this pattern based on a soup from Adam P. Goucher's apgsearch script, which was eventually optimized to a 6-glider synthesis[4] in November.

See also


  1. "Complementary blinker". The Life Lexicon. Stephen Silver. Retrieved on December 3, 2018.
  2. Achim Flammenkamp (September 7, 2004). "Most seen natural occurring ash objects in Game of Life". Retrieved on January 15, 2009.
  3. "Synthesising Oscillators". Retrieved on September 10, 2013.
  4. "Soup search results". Retrieved on November 9, 2014.

External links

  • 24P2.142 at Heinrich Koenig's Game of Life Object Catalogs