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6bobob$5bo4b$2o2bo4bo$2obo2bob2o$4b2o! #C [[ THUMBSIZE 2 THEME 6 GRID GRIDMAJOR 0 SUPPRESS THUMBLAUNCH ]] #C [[ AUTOSTART ]] #C [[ GPS 4 THUMBSIZE 2 ]]
Pattern type Oscillator
Number of cells 15
Bounding box 10×5
Frequency class 27.2
Period 8
Mod 4
Heat 9
Volatility 0.89
Strict volatility 0.89
Discovered by Robert Wainwright
Year of discovery Unknown

Blocker is a period-8 oscillator found by Robert Wainwright.[1] It is a useful dot sparker consisting of two blocks hassling an unnamed object which is a dying spark. It reappears halfway through its cycle rotated 180 degrees.

Blockers can also be infinitely connected by "sharing" blocks, as long as adjacent reactions are no more than one phase apart. They can also be connected with Coe's p8, which uses blocks as hasslers in a similar manner.

A blocker can double the period of a glider stream that is a multiple of 4 but not 8 by deleting every second glider.

x = 18, y = 12, rule = B3/S23 6bobo5bobo$5bo7bo$2o2bo4bo2bo4bo$2obo2bob2obo2bob2o$4b2o6b2o3$14bobo$ 5bo7bo$3ob2o2b2o2bo4bo$4o4b2obo2bob2o$4b2o6b2o! #C [[ THUMBSIZE 2 THEME 6 GRID GRIDMAJOR 0 SUPPRESS THUMBLAUNCH ]] #C [[ AUTOSTART THEME 6 GRID GPS 8 GRIDMAJOR 0 ZOOM 16 HEIGHT 480 THUMBLAUNCH THUMBSIZE 2 LOOP 8 ]]
Blockers sharing blocks
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RLE: here Plaintext: here


Blocker is about the sixteenth most common naturally-occurring oscillator in Achim Flammenkamp's census, being less common than mazing but more common than jam.[2] On Catagolue, it is the second most common period 8 oscillator, being less common than the figure eight but more common than Coe's p8.[3]

The first natural blocker stator variant, blocker on cap, occurred in September 2015.[4]

Glider synthesis

All strict still lifes with a population of 20 or fewer cells, as well as all oscillators and spaceships with 16 or fewer cells, are known to be glider-constructible. A glider synthesis of this object can be found in the infobox to the right.

See also


  1. Dean Hickerson's oscillator stamp collection. Retrieved on March 14, 2020.
  2. Achim Flammenkamp (September 7, 2004). "Most seen natural occurring ash objects in Game of Life". Retrieved on January 15, 2009.
  3. Adam P. Goucher. "Statistics". Catagolue. Retrieved on October 27, 2018.
  4. Billabob (September 9, 2015). Re: Soup search results (discussion thread) at the forums

External links

  • 15P8.1 at Heinrich Koenig's Game of Life Object Catalogs