Difference between revisions of "Greyship"
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{{Glossary}} | |||
[[Image:Greyship2_H_Holzwart.png|framed|right|A greyship]] | [[Image:Greyship2_H_Holzwart.png|framed|right|A greyship]] | ||
A '''greyship''' is a [[spaceship]] which contains a region of [[density]] 1/2 (generally the [[zebra stripes|stripes agar]]) that can be extended to an arbitrary size both horizontally and vertically. | A '''greyship''' is a [[spaceship]] which contains a region of [[density]] 1/2 (generally the [[zebra stripes|stripes agar]]) that can be extended to an arbitrary size both horizontally and vertically. | ||
The first greyships were found by [[Hartmut Holzwart]] and [[Jason Summers]] in | The first greyships were found by [[Hartmut Holzwart]] and [[Jason Summers]] in [[:Category:patterns found in 2005|2005]].<ref>{{cite web|url=http://pentadecathlon.com/lifeNews/2005/07/c2_and_2c4_greyships.html|title=c/2 and 2c/4 "greyships"|date=July 9, 2005|work=Game of Life News|author=Dave Greene|accessdate=February 24, 2018}}</ref><ref>{{cite web|url=http://pentadecathlon.com/lifeNews/2005/09/greyship_update.html|title=Greyship Update|date=September 6, 2005|work=Game of Life News|author=Dave Greene|accessdate=February 24, 2018}}</ref><ref>{{cite web|url=http://b3s23life.blogspot.com/2005/12/holiday-greyships-grey-no-longer.html|title=Holiday Greyships -- Grey No Longer!|date=December 10, 2005|work=Conway's Life: Work in Progress (weblog)|author=Dave Greene|accessdate=February 24, 2018}}</ref> These ships traveled orthogonally at [[c/2 orthogonal|c/2]]. Since then greyships have been found for speeds [[c/3 orthogonal|c/3]], [[c/4 orthogonal|c/4]], [[c/5 orthogonal|c/5]], and [[2c/5 orthogonal|2c/5]].<ref>{{cite web|url=http://pentadecathlon.com/lifeNews/2011/01/first_c5_greyship_and_a_new_c3.html|title=First c/5 greyship, and a new c/3|date=January 10,2011|work=Game of Life News|author=Dave Greene|accessdate=February 24, 2018}}</ref> | ||
==Types of greyships== | ==Types of greyships== | ||
Most known greyship components use the stripes agar and travel with-the-grain (parallel to the stripes); There are some known '''against-the-grain''' greyships, in which the stripes are perpendicular to the direction of travel; however, these are only known for a speed of c/2. | Most known greyship components use the stripes agar and travel with-the-grain (parallel to the stripes); There are some known '''against-the-grain''' greyships, in which the stripes are perpendicular to the direction of travel; however, these are only known for a speed of c/2.<ref>{{cite web|url=http://pentadecathlon.com/lifeNews/2005/12/new_perpendicular_greyships.html|title=New perpendicular greyships|date=December 16, 2005|work=Game of Life News|author=Dave Greene|accessdate=February 24, 2018}}</ref> | ||
Other than the stripes agar, there are a few known greyships that use the [[chicken wire]] agar. | Other than the stripes agar, there are a few known greyships that use the [[chicken wire]] agar<ref>{{cite web|url=http://pentadecathlon.com/lifeNews/2006/04/chickenwireagar_greyships.html|title=Chicken-Wire-Agar Greyships|date=April 3, 2006|work=Game of Life News|author=Dave Greene|accessdate=February 24, 2018}}</ref>, and some with other types of discontinuity.<ref>{{cite web|url=http://pentadecathlon.com/lifeNews/2005/12/hybrid_greyships_perpendicular.html | ||
|title=Hybrid greyships (perpendicular and parallel stripes)|date=December 16, 2005|work=Game of Life News|author=Dave Greene|accessdate=February 24, 2018}}</ref><ref>{{cite web|url=http://pentadecathlon.com/lifeNews/2005/12/fixedwidth_and_slippingstripe.html | |||
|title=Fixed-Width and Slipping-Stripe Greyships|date=December 18, 2005|work=Game of Life News|author=Dave Greene|accessdate=February 24, 2018}}</ref> A looser definition of greyship may also include ships with extensible, high-density agars of higher periods. | |||
==See also== | ==See also== | ||
[[Types of spaceships]] | *[[Types of spaceships]] | ||
==References== | ==References== | ||
Revision as of 09:59, 27 February 2018
A greyship
A greyship is a spaceship which contains a region of density 1/2 (generally the stripes agar) that can be extended to an arbitrary size both horizontally and vertically.
The first greyships were found by Hartmut Holzwart and Jason Summers in 2005.[1][2][3] These ships traveled orthogonally at c/2. Since then greyships have been found for speeds c/3, c/4, c/5, and 2c/5.[4]
Types of greyships
Most known greyship components use the stripes agar and travel with-the-grain (parallel to the stripes); There are some known against-the-grain greyships, in which the stripes are perpendicular to the direction of travel; however, these are only known for a speed of c/2.[5]
Other than the stripes agar, there are a few known greyships that use the chicken wire agar[6], and some with other types of discontinuity.[7][8] A looser definition of greyship may also include ships with extensible, high-density agars of higher periods.
See also
References
- ↑ Dave Greene (July 9, 2005). "c/2 and 2c/4 "greyships"". Game of Life News. Retrieved on February 24, 2018.
- ↑ Dave Greene (September 6, 2005). "Greyship Update". Game of Life News. Retrieved on February 24, 2018.
- ↑ Dave Greene (December 10, 2005). "Holiday Greyships -- Grey No Longer!". Conway's Life: Work in Progress (weblog). Retrieved on February 24, 2018.
- ↑ Dave Greene (January 10,2011). "First c/5 greyship, and a new c/3". Game of Life News. Retrieved on February 24, 2018.
- ↑ Dave Greene (December 16, 2005). "New perpendicular greyships". Game of Life News. Retrieved on February 24, 2018.
- ↑ Dave Greene (April 3, 2006). "Chicken-Wire-Agar Greyships". Game of Life News. Retrieved on February 24, 2018.
- ↑ Dave Greene (December 16, 2005). "Hybrid greyships (perpendicular and parallel stripes)". Game of Life News. Retrieved on February 24, 2018.
- ↑ Dave Greene (December 18, 2005). "Fixed-Width and Slipping-Stripe Greyships". Game of Life News. Retrieved on February 24, 2018.
External links
- Greyship at the Life Lexicon