Figure eight

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Figure eight
2bo$bobo$obobo$bobobo$2bobobo$3bobobo$4bobo$5bo! #C [[ THEME 6 GRID GRIDMAJOR 0 THUMBLAUNCH AUTOSTART ]] #C [[ GPS 4 THUMBSIZE 2 ]]
Pattern type Oscillator
Number of cells 12
Bounding box 10×10
Period 8
Mod 8
Heat 16.5
Volatility 1.00
Strict volatility 1.00
Discovered by Simon Norton
Year of discovery 1970

Figure eight (or less frequently, big beacon[1]) is a period 8 oscillator found by Simon Norton in 1970. With 12 cells in its initial phase, it is the smallest known period 8 oscillator, behind blocker at 15 cells. It is known that no period 8 oscillators exist with 10 or fewer cells.[2]

As a building block for larger oscillators

Because it produces a domino spark in one of its phases, it is useful for constructing larger oscillators that have period that is a multiple of eight. For example, it appears in tumbling T-tetson (period 8), sailboat (period 16), caterer on figure eight (the smallest period 24 oscillator), and figure eight on 36P22 (period 88).

As a reflector

Figure eight has the ability to act as a 90-degree glider reflector when it is combined with a block, boat and eater 1. The input path (in green) and output path (in red) of the glider are shown below.

Figure eight acting as a reflector
RLE: here


Figure eight is the tenth most common naturally-occurring oscillator in Achim Flammenkamp's census, being less common than the great on-off but more common than the spark coil.[3]

Image gallery

See also


  1. "Big beacon". The Life Lexicon. Stephen Silver. Retrieved on June 14, 2011.
  2. Mark Niemiec (1998). "Life Period-8 Oscillators". Retrieved on February 5, 2009.
  3. Achim Flammenkamp (September 7, 2004). "Most seen natural occurring ash objects in Game of Life". Retrieved on January 15, 2009.

External links

  • Figure 8 at Eric Weisstein's Treasure Trove of Life