Block agar

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The block agar is an agar consisting of blocks arranged periodically in rows and columns, with distance of 1 cell between any two adjacent rows or columns. The average field density of the block agar is 4/9.

Sometimes, more sparse arrangements of blocks are also described as block agars.[1]

Reactions in the block agar

x = 20, y = 17, rule = B3/S23 2ob2ob2ob2ob2ob2ob2o$2ob2ob2ob2ob2ob2ob2o2$2ob2ob2ob2ob2ob2ob2o$2ob2ob 2ob2ob2ob2ob2o2$2ob2ob2ob2ob2ob2ob2o$2ob2ob2ob2ob2ob2ob2o$9bo$2ob2ob2o b2ob2ob2ob2o$2ob2ob2ob2ob2ob2ob2o2$2ob2ob2ob2ob2ob2ob2o$2ob2ob2ob2ob2o b2ob2o2$2ob2ob2ob2ob2ob2ob2o$2ob2ob2ob2ob2ob2ob2o! #C [[ THUMBSIZE 2 THEME 6 GRID GRIDMAJOR 0 SUPPRESS THUMBLAUNCH ]] #C [[ THUMBSIZE 2 ZOOM 16 HEIGHT 450 GPS 8 THEME Book AUTOSTART T 0 PAUSE 3 T 22 PAUSE 2 LOOP 23 ]]
A pattern doomed by a virus (from Lifeline Volume 9)
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If an alive cell ("virus") is added to the block agar so that it touches the corners of four blocks, the agar self-repairs in two ticks. However, when a single cell is added so that it touches cells of two different blocks, it initiates an expanding disintegration of the agar.[2][3]

Space clearers for the block agar and for one quarter of the block agar were found by Hartmut Holzwart;[4] these space clearers are reactions that expand through the infinite agar and leave empty space behind.[5]

There are known p3 lightspeed "trimmers" on an array of blocks with zebra stripes boundary.[6]

Finite patches

Finite rectangular patches of the block agar (n-by-m block arrays) are pseudo still lifes; the simplest example is the bi-block, which is the 1 × 2 block array.

x\y 1 2 3 ...
1 1×1 blocks.png 2×1 blocks.png 3×1 blocks.png
2 1×2 blocks.png 2×2 blocks.png 3×2 blocks.png
3 1×3 blocks.png 2×3 blocks.png 3×3 blocks.png
...

Glider synthesis

x = 39, y = 45, rule = B3/S23 bo$2bo$3o2$28bo$28bobo$6bobo19b2o$7b2o$7bo5$38bo$18bo5bo11b2o$17bobo3b obo11b2o$17bo2bobo2bo$18b2o3b2o3$7b2ob2ob2ob2o$7b2ob2ob2ob2o3b2o$20bo 2bo$7b2ob2ob2ob2o3b2o$7b2ob2ob2ob2o3$18b2o3b2o8b3o$17bo2bobo2bo7bo$17b obo3bobo8bo$18bo5bo6$7bo$7b2o$6bobo19b2o$28bobo$28bo2$3o$2bo$bo! #C [[ THUMBSIZE 2 THEME 6 GRID GRIDMAJOR 0 SUPPRESS THUMBLAUNCH ]] #C [[ THUMBSIZE 2 ZOOM 10 HEIGHT 500 GPS 8 THEME Book AUTOSTART T 0 PAUSE 1 T 20 PAUSE 3 T 68 PAUSE 2 LOOP 69 ]]
A way to extend a 2 × n block array[7]
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In 2005, Jason Summers found a way to extend any 2 × n block array. The method involves building a constellation of beehive and four loaves and hitting it with 8 gliders.[7]

On December 3, 2015, Martin Grant found a method of constructing a 3 × n block array via glider synthesis.[8]

On May 6, 2020, Goldtiger997 found a method of constructing a 4 × n block array.[9]

The problem of constructing an arbitrary m-by-n block array is currently still unsolved.[10][11]

See also

Objects in which a temporary 2 × 2 block array is formed for several consecutive phases:

References

  1. Lifeline Volume 3#Page 29
  2. Martin Gardner, Wheels, Life, and Other Mathematical Amusements, The Game of Life, Part II
  3. Lifeline Volume 9#Page 6
  4. Hartmut Holzwart (July 2, 2020). Re: Agar crawlers (discussion thread) at the ConwayLife.com forums
  5. Dave Greene (April 15, 2023). Re: Thread for basic questions (discussion thread) at the ConwayLife.com forums
  6. wildmyron (September 21, 2020). Re: 'Skimmers' (discussion thread) at the ConwayLife.com forums
  7. 7.0 7.1 Heinrich Koenig (April 20, 2005). "Block Array Constructions". Game of Life News.
  8. Martin Grant (December 3, 2015). Re: Synthesising Oscillators (discussion thread) at the ConwayLife.com forums
  9. Goldtiger997 (May 6, 2020). Re: Synthesising Oscillators (discussion thread) at the ConwayLife.com forums
  10. https://conwaylife.com/forums/viewtopic.php?p=140125#p140125
  11. https://conwaylife.com/forums/viewtopic.php?p=146722#p146722