Caterloopillar
- This article is about the adjustable spaceship. For the 17c/45 crawler ship, see Caterpillar.
Caterloopillar | |||||||
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Pattern type | Spaceship | ||||||
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Number of cells | 232815 | ||||||
Bounding box | 734 × 514927 | ||||||
Direction | Orthogonal | ||||||
Period | 2000 (mod: Unknown) | ||||||
Speed | c/8 | 250c/2000 | ||||||
Heat | 220775.0 | ||||||
Kinetic symmetry | n | ||||||
Discovered by | Michael Simkin | ||||||
Year of discovery | 2016 | ||||||
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Caterloopillar is the name given to a family of spaceships which provides a general solution for self-supporting orthogonal travel at a wide range of speeds.
The engineless design is made up of two major parts, the front and the back. In Caterloopillar, each of these parts is a universal constructor that constructs the building blocks of the other part, while also reading and moving a construction tape. As the name suggests, this creates somewhat paradoxical design, similar to the "strange loop" concept.[1]
The Caterloopillar was voted Pattern of the Year for 2016 on the ConwayLife.com forums.[2]
A Golly script is available that can generate spaceships of all supported speeds and lower than c/4. The script does not work for speeds of the form m/(8k+2) and m/(8k+6).
History
The general idea of adjustable speed spaceships was proposed by David Bell in October 2006 on the LifeCA mailing list[3], and independently by Jason Summers in December 2007[3]. Hartmut Holzwart revived discussion about the idea in September 2014 on the ConwayLife.com forums.[4]
During those discussions, Alexey Nigin in 2014 proposed a novel way of construction that would avoid helices. Instead it would use two streams upward and downward, that create each other using slow salvos.[5] Surprisingly enough the final design of the first Caterloopillar[6] was very close to his description.
Alexey Nigin's initial design proposal was purely theoretical. The first example showing that the idea could be efficiently implemented was found by Michael Simkin a few days after the initial suggestion.[7]
The name was also extensively discussed, with suggestions including strange loop,[8] strange-caterloopillar,[9] pushmi-pullyou[10] and caterloop,[11] finally arriving at Caterloopillar in June 2015.[12]
Implementation
The first Caterloopillar was constructed by Michael Simkin and completed on April 9, 2016; this Caterloopillar has a speed of c/8. Caterloopillars with many other speeds can be constructed using a slightly modified design. The major limitation of this implementation is upper bound of speed c/4, as the signal transferring is done by converting a still life into a glider and back, thus limiting the moving speed of the tape to c/4 (the speed of the glider).
Caterloopillars of various other speeds (see list of spaceships for a full list) were later constructed using the script,[13][14][15][16][17] the first three being c/9, c/11 and c/12 orthogonal, respectively. One of the most notable Caterloopillars is a 31c/240 one smaller than the Centipede, a previous record holder for that speed which was not based on Caterloopillar technology. It has since been surpassed by the former record holder, the silverfish, and the current record holder, the leaf bug.
In general, faster Caterloopillars appear to require more cells.
See also
- Caterpillar
- Orthogonoid
- Nico Brown's strictly volatile oscillator family with a similar design[18]
References
- ↑ Strange loop at Wikipedia
- ↑ Alexey Nigin (June 3, 2017). Pattern of the Year 2016 (Results) (discussion thread) at the ConwayLife.com forums
- ↑ 3.0 3.1 Hartmut Holzwart (September 12, 2014). Re: David Bell's engineless caterpillar idea revisited (discussion thread) at the ConwayLife.com forums
- ↑ Hartmut Holzwart (September 11, 2014). David Bell's engineless caterpillar idea revisited (discussion thread) at the ConwayLife.com forums
- ↑ Alexey Nigin (November 12, 2014). Re: David Bell's engineless caterpillar idea revisited (discussion thread) at the ConwayLife.com forums
- ↑ Michael Simkin (April 9, 2016). Caterloopillar WIP (all speeds < c/4) (discussion thread) at the ConwayLife.com forums
- ↑ Michael Simkin (November 14th, 2014). Re: David Bell's engineless caterpillar idea revisited (discussion thread) at the ConwayLife.com forums
- ↑ Ivan Fomichev (November 15, 2014). Re: David Bell's engineless caterpillar idea revisited (discussion thread) at the ConwayLife.com forums
- ↑ Dave Greene (June 19, 2015). Re: David Bell's engineless caterpillar idea revisited (discussion thread) at the ConwayLife.com forums
- ↑ Ivan Fomichev (November 22, 2014). Re: David Bell's engineless caterpillar idea revisited (discussion thread) at the ConwayLife.com forums
- ↑ Michael Simkin (November 15, 2014). Re: David Bell's engineless caterpillar idea revisited (discussion thread) at the ConwayLife.com forums
- ↑ Michael Simkin (June 20, 2015). Re: David Bell's engineless caterpillar idea revisited (discussion thread) at the ConwayLife.com forums
- ↑ Michael Simkin (April 15, 2016). Re: Caterloopillar WIP (all speeds < c/4) (discussion thread) at the ConwayLife.com forums
- ↑ Michael Simkin (April 15, 2016). Re: Caterloopillar WIP (all speeds < c/4) (discussion thread) at the ConwayLife.com forums
- ↑ Michael Simkin (April 16, 2016). Re: Caterloopillar WIP (all speeds < c/4) (discussion thread) at the ConwayLife.com forums
- ↑ thunk (April 16, 2016). Re: Caterloopillar WIP (all speeds < c/4) (discussion thread) at the ConwayLife.com forums
- ↑ Michael Simkin (April 17, 2016). Re: Caterloopillar WIP (all speeds < c/4) (discussion thread) at the ConwayLife.com forums
- ↑ Dave Greene (December 4, 2022). Re: NewLifeCA Back Issues (discussion thread) at the ConwayLife.com forums
External links
- Caterloopillar at the Life Lexicon
- Caterloopillar WIP (all speeds < c/4) (discussion thread) at the ConwayLife.com forums
- David Bell's engineless caterpillar idea revisited (discussion thread) at the ConwayLife.com forums
- Caterloopillar GitHub repository
- Caterloopillar c/8 RLE file
- Patterns
- Spaceships with between 100,000 and 999,999 cells
- Periodic objects with minimum population between 100,000 and 999,999
- Patterns with between 100,000 and 999,999 cells
- Patterns found by Michael Simkin
- Patterns found in 2016
- Outer-totalistically endemic patterns
- Spaceships
- Spaceships with period 2000
- Orthogonal spaceships
- Spaceships with speed c/8
- Spaceships with unsimplified speed 250c/2000
- Spaceships with heat between 100,000 and 999,999
- Spaceships with n symmetry
- Pattern of the Year top contenders
- Pattern of the Year winners
- Non-monotonic spaceships
- Adjustable spaceships
- Universal constructors