Block agar: Difference between revisions

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#REDIRECT [[Block#Block arrays]]
{{Glossary}}
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.{{refn|[[Lifeline Volume 3#Page 29]]}}
 
== Reactions in the block agar ==
 
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.{{refn|Martin Gardner, ''[[Wheels, Life, and Other Mathematical Amusements]]'', The Game of Life, Part II}}
 
[[Space clearer]]s for the block agar and for one quarter of the block agar were found by [[Hartmut Holzwart]];<ref name="post99952" /> these space clearers are reactions that expand through the infinite agar and leave empty space behind.<ref name="post160515" />
 
There are known p3 lightspeed "trimmers" on an array of blocks with zebra stripes boundary.<ref name="post104616" />
 
== Finite patches ==
Finite rectangular patches of the block agar (''n''-by-''m'' '''block arrays''') are [[pseudo still life]]s; the simplest example is the [[bi-block]], which is the {{times|1|2}} block array.
 
{| class="wikitable" style="margin-left:auto; margin-right:auto; clear:both; text-align:center"
! x\y
! 1
! 2
! 3
! ...
|-
! 1
! [[File:1×1 blocks.png]]
! [[File:2×1 blocks.png]]
! [[File:3×1 blocks.png]]
! rowspan="3" | →
|-
! 2
! [[File:1×2 blocks.png]]
! [[File:2×2 blocks.png]]
! [[File:3×2 blocks.png]]
|-
! 3
! [[File:1×3 blocks.png]]
! [[File:2×3 blocks.png]]
! [[File:3×3 blocks.png]]
|-
! ...
! colspan="3" | ↓
! ↘
|}
 
=== Glider synthesis ===
 
In {{year|2005}}, Jason Summers found a way to extend any {{times|2|''n''}} block array.<ref name="lifenews_2005_04" />
 
On December 3, {{year|2015}}, [[Martin Grant]] found a method of constructing a {{times|3|''n''}} block array via [[glider synthesis]].<ref name="post25637" />
 
On May 6, {{year|2020}}, [[Goldtiger997]] found a method of constructing a {{times|4|''n''}} block array.<ref name="post96210" />
 
The [[problem]] of constructing an arbitrary ''m''-by-''n'' block array is still unsolved.<ref>https://conwaylife.com/forums/viewtopic.php?p=140125#p140125</ref><ref>https://conwaylife.com/forums/viewtopic.php?p=146722#p146722</ref>
 
== References ==
<references>
<ref name="lifenews_2005_04">{{cite web
|url    = https://web.archive.org/web/20160409092832/http://pentadecathlon.com/lifeNews/2005/04/block_array_constructions.html
|title  = Block Array Constructions
|author = Heinrich Koenig
|date  = April 20, 2005
|work  = Game of Life News
}}</ref>
<ref name="post25637">{{LinkForumThread
|format = ref
|p      = 25637
|title  = Re: Synthesising Oscillators
|author = Martin Grant
|date  = December 3, 2015
}}</ref>
<ref name="post96210">{{LinkForumThread
|format = ref
|p      = 96210
|title  = Re: Synthesising Oscillators
|author = Goldtiger997
|date  = May 6, 2020
}}</ref>
<ref name="post99952">{{LinkForumThread
|format = ref
|p      = 99952
|title  = Re: Agar crawlers
|author = Hartmut Holzwart
|date  = July 2, 2020
}}</ref>
<ref name="post104616">{{LinkForumThread
|format = ref
|p      = 104616
|title  = Re: 'Skimmers'
|author = wildmyron
|date  = September 21, 2020
}}</ref>
<ref name="post160515">{{LinkForumThread
|format = ref
|p      = 160515
|title  = Re: Thread for basic questions
|author = Dave Greene
|date  = April 15, 2023
}}</ref>
</references>
 
[[Category:Stable agars]]
[[Category:Agars]]
[[Category:Pseudo still lifes]]
[[Category:Problems]]
__NOTOC__

Revision as of 20:06, 18 April 2023

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

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]

Space clearers for the block agar and for one quarter of the block agar were found by Hartmut Holzwart;[3] these space clearers are reactions that expand through the infinite agar and leave empty space behind.[4]

There are known p3 lightspeed "trimmers" on an array of blocks with zebra stripes boundary.[5]

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 →
2
3
... ↓ ↘

Glider synthesis

In 2005, Jason Summers found a way to extend any 2 × n block array.[6]

On December 3, 2015, Martin Grant found a method of constructing a 3 × n block array via glider synthesis.[7]

On May 6, 2020, Goldtiger997 found a method of constructing a 4 × n block array.[8]

The problem of constructing an arbitrary m-by-n block array is still unsolved.[9][10]

References

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