Beacon

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Beacon
2o$2o$2b2o$2b2o! #C [[ THUMBSIZE 2 THEME 6 GRID GRIDMAJOR 0 SUPPRESS THUMBLAUNCH ]] #C [[ AUTOSTART ]] #C [[ HEIGHT 600 WIDTH 600 THUMBSIZE 3 ZOOM 60 GPS 2 LOOP 2 ]]
Pattern type Oscillator
Oscillator type Babbling brook
Family Beacon
Number of cells 6
Bounding box 4 × 4
Frequency class 8.8
Period 2
Mod 2
Heat 2
Volatility 0.25
Strict volatility 0.25
Rotor type Diagonal on-off
Discovered by John Conway
Year of discovery 1970

The beacon is a common period-2 oscillator composed of two diagonally touching blocks. It was found by John Conway in March 1970.[1]

The beacon is the simplest on-off. Its rotor, known as diagonal on-off, can be supported by several different stators: the next smallest is seen in eater plug. It can, in some sense, be considered a billiard table.[2] It is the smallest oscillator whose population is not constant.

Occurrence

See also: List of common oscillators

The beacon is the third most common oscillator in Achim Flammenkamp's census (after the blinker and toad).[3] It is also the thirteenth most common object on Adam P. Goucher's Catagolue.[4] In D2 diagonal symmetry, it is the eighth most common object, being more common than the tub but less common than the ship.

Uses

Beacons are significantly more common in diagonal symmetry than asymmetrically, so they can reform when hit, such as in the p26 pre-pulsar shuttle. The p24 shuttle, also having diagonal symmetry, contains a beacon, although this is incidental and not a catalyst.

A beacon can perform a snake-type catalysis in one of its two phases. Specifically, in the last generation before triggering the boat-bit reaction, the beacon is in the dense phase.

Reactions

x = 18, y = 18, rule = B3/S23 bo$2bo$3o8$4b2o$4bo$7bo$6b2o2$15b2o$15bobo$15bo! #C [[ THUMBSIZE 2 THEME 6 GRID GRIDMAJOR 0 SUPPRESS THUMBLAUNCH ]] #C [[ HEIGHT 600 WIDTH 600 ZOOM 18 X -4 Y 4 GPS 15 AUTOSTART T 0 PAUSE 2 T 72 PAUSE 2 LOOP 73 ]]
Beacon is hit by two gliders and shifts by (4,4), inverts phase and emits two pi-heptominoes that become a half-bakery and pairs of ponds, boats and blinkers. Occurs in the exhaust of a seminatural p480 ark (Catagoluehere)
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In other rules

tlife and related rules have the isotropic transition S4q, making beacon an 8-cell still life systematically named "block-tie".

See also

References

  1. Dean Hickerson's oscillator stamp collection. Retrieved on March 14, 2020.
  2. Dave Greene (July 3, 2019). Re: Thread for basic questions (discussion thread) at the ConwayLife.com forums
  3. Achim Flammenkamp (September 7, 2004). "Most seen natural occurring ash objects in Game of Life". Retrieved on January 15, 2009.
  4. Adam P. Goucher. "Statistics". Catagolue. Retrieved on June 24, 2016.

External links