Total aperiodic

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Total aperiodic
x = 59, y = 57, rule = B3/S23 41bo$40b3o$39b2obo5bo$39b3o5b3o$40b2o4bo2b2o3b3o$46b3o4bo2bo$56bo$56bo $56bo$40b3o12bo$40bo2bo$40bo$40bo$41bo7$38b3o$38bo2bo11bo$38bo13b3o$ 38bo12b2obo$38bo12b3o$39bo12b2o3$35b3o$34b5o$34b3ob2o7b2o5bo2bo$37b2o 7b4o8bo$46b2ob2o3bo3bo$48b2o5b4o3$20bo$21bo$b2o13bo4bo32b3o$4o13b5o34b o$2ob2o51bo$2b2o51bo$36bo$37bo$21b2o10bo3bo$22b2o10b4o15b2o$21b2o27b3o b2o$21bo28b5o$51b3o2$22b2o$13b4o4b4o$12bo3bo4b2ob2o$b5o10bo6b2o$o4bo9b o$5bo$4bo! #C [[ THUMBSIZE 2 THEME 6 GRID GRIDMAJOR 0 SUPPRESS THUMBLAUNCH ]]
Pattern type Miscellaneous
Number of cells 182
Bounding box 59×57
Discovered by Bill Gosper
Year of discovery 1997

A finite pattern is total aperiodic if it evolves in such a way that no cell in the plane is eventually periodic. The first example was found by Bill Gosper on November 16, 1997. A few days later, on November 19, he found the much smaller example that consists of three copies of backrake 2 (by David Buckingham), shown to the right.[1]

On June 24, 2004, Gosper found that a block can be added to the pattern to make the total periodic pattern shown below, in which every cell eventually becomes periodic (albeit incredibly slowly). The block remains untouched for about 363 generations. It deletes its nth glider (and is shifted) at about generation 357.5+5.5n.[2]

Image gallery

Total periodic
RLE: here


  1. Paul Callahan (December 20, 1997). "Totally aperiodic patterns". Paul Callahan's Page of Conway's Life Miscellany. Retrieved on November 9, 2020.
  2. Jason Summers' jslife oversize pattern collection.

External links