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x = 13, y = 19, rule = B3/S23 b2o6b2o$o2bo4bo2bo$o2bo4bo2bo$o2bo4bo2bo$b2o6b2o3$7bo$5bo2bob2o$6b2o2b 2o3$6b4o$5b6o$4b8o$3b2o6b2o$4b8o$5b6o$6b4o! #C [[ THUMBSIZE 2 THEME 6 GRID GRIDMAJOR 0 SUPPRESS THUMBLAUNCH ]] #C [[ AUTOSTART ]] #C [[ GPS 3 ZOOM 12 LOOP 15 ]]
Pattern type Oscillator
Number of cells 42
Bounding box 18×22
Period 15
Mod 15
Heat 47.9
Volatility 0.98
Strict volatility 0.98
Discovered by Robert Wainwright
Year of discovery 1984

Jolson (also known as Al Jolson[note 1]) is a period-15 oscillator consisting of two blocks hassled by two pentadecathlons. It was found by Robert Wainwright in November 1984[1] and named by Bill Gosper.

The hassling mechanism requires two domino sparks, constantly 3 generations apart, provided by sparkers of period 9 or above (e.g. Merzenich's p31). A period 9 version that uses two snackers is possible (see below), but p14 (with tetradecathlons) is impossible.[2]

Image gallery

The period 9 version of Jolson
Download RLE: click here
One of the phases of Jolson, which led to its name


  1. The name is a reference to Al Jolson, a famous American singer.


  1. Dean Hickerson's oscillator stamp collection. Retrieved on March 14, 2020.
  2. Mark Niemiec (August 14, 2019). Re: Oscillator Discussion Thread (discussion thread) at the forums

External links

  • 42P15.1 at Heinrich Koenig's Game of Life Object Catalogs