Difference between revisions of "Herschel"

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__NOTOC__{{Methuselah|l=128|name=Herschel|pname=herschel|c=7|bx=3|by=4|life105=true|life106=true|plaintext=true|rle=true}}
{{Methuselah
The '''Herschel''' (or, much less commonly, '''D-heptomino'''<ref>{{cite web|url=http://www.argentum.freeserve.co.uk/lex_d.htm#dheptomino |title=Life Lexicon "D" |publisher=Stephen Silver |date=February 28, 2006|accessdate=March 25, 2009}}</ref><ref>{{cite web|url=http://www.conwaylife.com/wiki/index.php?title=Lifeline_Volume_1 |title=Lifeline Number 1 |publisher=Robert Wainwright |date=March 1971}}</ref> or '''J-heptomino'''<ref>{{cite web|url=http://www.argentum.freeserve.co.uk/lex_j.htm#jheptomino|title=J-heptomino|publisher=The Life Lexicon|author=Stephen Silver|accessdate=June 13, 2009}}</ref>) is a [[heptomino]] shaped like the lowercase letter ''h'', which occurs at generation 20 of the [[B-heptomino]]. It evolves into two [[block]]s, two [[glider]]s and a [[ship]] after 128 generations, and also produces a [[phi spark]].
|name         = Herschel
|pname       = herschel
|c           = 7
|bx           = 3
|by           = 4
|l            = 128
|f            = 22
|mcps        = 7
|discoverer  = John Conway
|discoveryear = 1970
|rulemin      = B3/S23
|rulemax      = B38/S23
|rulespecial  = [[Conway's Game of Life|Conway Life]]
|isorulemin  = B3/S23
|isorulemax  = B38/S23
|synthesis    = 3
|synthesisRLE = true
|plaintext   = true
|rle         = true
}}
The '''Herschel''' (or, much less commonly, '''D-heptomino'''<ref>{{CiteLexicon|file=lex_d.htm#dheptomino|name=D|accessdate=March 25, 2009}}</ref><ref>{{citeLifeline|vol=1}}</ref> or '''J-heptomino'''<ref>{{CiteLexicon|file=lex_j.htm#jheptomino|name=J-heptomino|accessdate=June 13, 2009}}</ref>) is a [[heptomino]] shaped like the lowercase letter ''h'', which occurs at generation 20 of the [[B-heptomino]]. It evolves into two [[block]]s, two [[glider]]s and a [[ship]] after 128 [[generation]]s, and also produces a [[phi spark]].


==Common uses==
==Common uses==
Herschels are a recognizable "bottleneck" stage of a very common progression of three small active objects, frequently seen during the evolution of chaotic patterns.  An [[R-pentomino]] evolves after 28 ticks into a [[B-heptomino]] a dozen cells away from the starting point, plus some active trailing junk; the B-heptomino then evolves into a Herschel in another 20 ticks, while traveling another 8 cells in the same direction. 22 ticks and 5 cells later yet the Herschel evolves into a backwards escaping glider (known as the [[first natural glider]], FNG), and a final, unnamed bottleneck pattern that evolves into a larger explosion before settling down.
Herschels are a recognizable "bottleneck" stage of a very common progression of three small active objects, frequently seen during the evolution of chaotic patterns.  An [[R-pentomino]] evolves after 28 ticks into a [[B-heptomino]] a dozen cells away from the starting point, plus some active trailing junk; the B-heptomino then evolves into a Herschel in another 20 ticks, while traveling another 8 cells in the same direction. 22 ticks and 5 cells later yet the Herschel evolves into a backwards escaping glider (known as the [[first natural glider]], FNG), and a final, unnamed bottleneck pattern that evolves into a larger explosion before settling down.


The unusual distance that R-pentominoes and B-heptominoes travel during their evolution into Herschels has allowed for the development of a growing collection of [[Herschel conduit]]s, which use [[catalyst]]s to modify the 128-step reaction.  Instead of producing the still lifes and gliders described above, an input Herschel "bounces off" a series of eaters and other catalysts and produces a new output Herschel some distance away.  In some cases, the active reaction travels directly "through" one or more [[transparent catalyst]]s, destroying it completely and re-creating it in the same location several ticks later.  The output Herschel can then become the input for another conduit, which may continue in the same direction or turn left or right.  If it eventually forms a closed loop, the result is a Herschel-based [[oscillator]] or [[gun]].
The unusual distance that R-pentominoes and B-heptominoes travel during their evolution into Herschels has allowed for the development of a growing collection of [[Herschel conduit]]s, which use [[catalyst]]s to modify the 128-step reaction.  Instead of producing the still lifes and gliders described above, an input Herschel "bounces off" a series of eaters and other catalysts and produces a new output Herschel some distance away.  In some cases, the active reaction travels directly "through" one or more [[transparent]] catalysts, destroying it completely and re-creating it in the same location several ticks later.  The output Herschel can then become the input for another conduit, which may continue in the same direction or turn left or right.  If it eventually forms a closed loop, the result is a Herschel-based [[oscillator]] or [[gun]].


Most (but not all) conduits only engage the Herschel after its splitting into its final offspring and the FNG. Dealing with the latter is crucial in assembling a track from separate conduits: it is fired in a direction where it would commonly collide with a previous conduit's catalysts. [[Eater 5]] is one of the most convenient solutions for this task.
Most (but not all) conduits only engage the Herschel after its splitting into its final offspring and the FNG. Dealing with the latter is crucial in assembling a track from separate conduits: it is fired in a direction where it would commonly collide with a previous conduit's catalysts. [[Eater 5]] is one of the most convenient solutions for this task.
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==Image gallery==
==Image gallery==
{|
{|
|-
|-
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==See also==
==See also==
*[[Conduit 1]]
* [[B-heptomino]]
*[[Herschel grandparent]]
* [[Conduit 1]]
*[[Herschel parent]]
* [[Herschel great-grandparent]]
* [[Herschel grandparent]]
* [[Herschel parent]]


==References==
==References==
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==External links==
==External links==
{{LinkWeisstein|Herschel.html}}
{{LinkLexicon|lex_h.htm#herschel}}
{{LinkLexicon|lex_h.htm#herschel}}
__NOTOC__

Revision as of 01:31, 3 December 2020

Herschel
x = 3, y = 4, rule = B3/S23 o$3o$obo$2bo! #C [[ THUMBSIZE 2 THEME 6 GRID GRIDMAJOR 0 SUPPRESS THUMBLAUNCH ]]
Pattern type Methuselah
Number of cells 7
Bounding box 3 × 4
MCPS 7
Lifespan 128 generations
Final population 22
L/I 18.3
F/I 3.1
F/L 0.172
L/MCPS 18.3
Discovered by John Conway
Year of discovery 1970

The Herschel (or, much less commonly, D-heptomino[1][2] or J-heptomino[3]) is a heptomino shaped like the lowercase letter h, which occurs at generation 20 of the B-heptomino. It evolves into two blocks, two gliders and a ship after 128 generations, and also produces a phi spark.

Common uses

Herschels are a recognizable "bottleneck" stage of a very common progression of three small active objects, frequently seen during the evolution of chaotic patterns. An R-pentomino evolves after 28 ticks into a B-heptomino a dozen cells away from the starting point, plus some active trailing junk; the B-heptomino then evolves into a Herschel in another 20 ticks, while traveling another 8 cells in the same direction. 22 ticks and 5 cells later yet the Herschel evolves into a backwards escaping glider (known as the first natural glider, FNG), and a final, unnamed bottleneck pattern that evolves into a larger explosion before settling down.

The unusual distance that R-pentominoes and B-heptominoes travel during their evolution into Herschels has allowed for the development of a growing collection of Herschel conduits, which use catalysts to modify the 128-step reaction. Instead of producing the still lifes and gliders described above, an input Herschel "bounces off" a series of eaters and other catalysts and produces a new output Herschel some distance away. In some cases, the active reaction travels directly "through" one or more transparent catalysts, destroying it completely and re-creating it in the same location several ticks later. The output Herschel can then become the input for another conduit, which may continue in the same direction or turn left or right. If it eventually forms a closed loop, the result is a Herschel-based oscillator or gun.

Most (but not all) conduits only engage the Herschel after its splitting into its final offspring and the FNG. Dealing with the latter is crucial in assembling a track from separate conduits: it is fired in a direction where it would commonly collide with a previous conduit's catalysts. Eater 5 is one of the most convenient solutions for this task.

Etymology

The term "Herschel" is attributed to John Conway, who very early in the history of Life investigated the fates of all polyominoes up to at least 7 bits [4]. The name is commonly ascribed to the Herschel heptomino's similarity to a planetary symbol ♄ erroneously attributed to Uranus (discovered by William Herschel in 1781.) However, in point of fact a Herschel closely resembles the symbol for Saturn, but bears no particular resemblance to either of the symbols used for Uranus. So the appropriate name might actually be "Huygens" -- but "Herschel" is now universally used by tradition.

Image gallery

Generation 128 of a Herschel

See also

References

  1. "D". The Life Lexicon. Stephen Silver. Retrieved on March 25, 2009.
  2. Robert Wainwright (March 1971). Lifeline, vol 1.
  3. "J-heptomino". The Life Lexicon. Stephen Silver. Retrieved on June 13, 2009.
  4. Martin Gardner (October, 1970). "Mathematical Games: The fantastic combinations of John Conway's new solitaire game "life"". Retrieved on August 2, 2009.

External links