p42 glider shuttle

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p42 glider shuttle
x = 32, y = 32, rule = B3/S23 22b2o$21bo2bo$10bo13bo$9bobo12bo$10bo7bo3bobo$17bo3bobo$8b5o4bo4bo$7bo 4bo5b4o4b2o$6bob2o16b2o2b2o$3bo2bobo15b2obo2b2o$2bobobo9bo7b3o$3bo2bo 4b3o3b2o$6b2o3b2o3b2o$11bo13b2o$25b2o2$10bobo$5b2o4b2o$4bo2bo3bo7b2o$ 7bo10bo2bo2b2o$7bo10bobo4bo2bo$bo3bobo11bo5bobobo$o3bobo15b2obo2bo$o4b o16bo2bo$b4o4b2o8bo4bo$9b2o2b2o4b5o$7b2obo2b2o$7b3o11bo$20bobo$21bo$8b 2o$8b2o! #C [[ THUMBSIZE 2 THEME 6 GRID GRIDMAJOR 0 SUPPRESS THUMBLAUNCH ]] #C [[ AUTOSTART ]] #C [[ GPS 6 ZOOM 8 LOOP 42 ]]
Pattern type Oscillator
Oscillator type Relay
Number of cells 143
Bounding box 32×32
Period 42
Mod 21
Heat 56.1
Volatility 0.75
Strict volatility 0.33
Discovered by Noam Elkies
Year of discovery 1994

The p42 glider shuttle is a period-42 shuttle oscillator discovered by Noam Elkies in 1994. It was the first non-trivial period 42 oscillator to be discovered[1][note 1] and is based on a period 66 oscillator discovered by Robert Wainwright in September 1984. It consists of two copies of eater 3 and four copies of unix to shuttle two gliders back and forth. By increasing the distance between the two reflectors, oscillators of periods 42 + 24n can be created. Dean Hickerson found that the distance between the reflectors could be decreased using a custom period 6 oscillator to create a period 18 glider shuttle. In April 1992 Hickerson created another related oscillator by crossing two pairs of gliders using rephasers, which allowed the construction of oscillators of periods 246 + 24n.

Image gallery

A p18 glider shuttle using a custom period 6 oscillator by Dean Hickerson
RLE: here
A related p246 oscillator discovered by Dean Hickerson
RLE: here

See also


  1. A period-42 oscillator, unix on 44P7.2, can be constructed from two sparkers (unix and 44P7.2) both of which were known by 1977. However, this type of oscillator is generally considered "boring", and thus not counted despite technically being non-trivial.


  1. Dean Hickerson's oscillator stamp collection. Retrieved on July 8, 2010.

External links