Life Lexicon (M)
Author: Stephen A. Silver
Description: Part of Stephen Silver's Life Lexicon.

Introduction | Bibliography

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:mango (p1)

    .OO..
    O..O.
    .O..O
    ..OO.

:mathematician (p5) Found by Dave Buckingham, 1972.

    ....O....
    ...O.O...
    ...O.O...
    ..OO.OO..
    O.......O
    OOO...OOO
    .........
    OOOOOOOOO
    O.......O
    ...OOOO..
    ...O..OO.

:Max A name for the smallest known spacefiller. The name represents the fact that the growth rate is the fastest possible. (This has not quite been proved, however. There remains the possibility, albeit not very likely, that a periodic agar could have an average density greater than 1/2, and a spacefiller stretching such an agar at the same speed as the known spacefillers would have a faster average growth rate.)

:mazing (p4) In terms of its minimum population of 12 this ties with mold as the smallest p4 oscillator. Found by Dave Buckingham in December 1973. For some constructions using mazings, see popover and sixty-nine.

    ...OO..
    .O.O...
    O.....O
    .O...OO
    .......
    ...O.O.
    ....O..

:medium fish = MWSS

:metacatacryst A 52-cell pattern exhibiting quadratic growth. Found by Nick Gotts, December 2000. This is currently the smallest known pattern (in terms of initial population) with superlinear growth. See also catacryst.

:metamorphosis An oscillator built by Robert Wainwright that uses the following reaction (found by Bill Gosper) to turn gliders into LWSS, and converts these LWSS back into gliders by colliding them head on. (There are in fact two ways to do the following reaction, because the spark of the twin bees shuttle is symmetric.)

    ...................O.........
    ....................O........
    ..................OOO........
    .............................
    .............................
    .............................
    .............................
    .............................
    ............O...O.....O.OO...
    OO.........O.....O....O.O.O..
    OO.........O.........O....O..
    ...........OO...O.....O.O.O..
    .............OOO......O.OO...
    .............................
    .............OOO.............
    ...........OO...O............
    OO.........O...............OO
    OO.........O.....O.........OO
    ............O...O............

:metamorphosis II An oscillator built by Robert Wainwright in December 1994 based on the following p30 glider-to-LWSS converter. This converter was first found by Paul Rendell, January 1986 or earlier, but wasn't widely known about until Paul Callahan rediscovered it in December 1994.

    ......................O.
    .....................O..
    .....................OOO
    ........................
    ........................
    .........O.O............
    .........O..O...........
    OO..........OO..........
    OO........O...OO........
    .....OO.....OO..........
    ....O....O..O...........
    .........O.O............
    ........................
    ........................
    ........................
    ........................
    ................O.......
    ...............OOO......
    ..............OOOOO.....
    .............O.O.O.O....
    .............OO...OO....
    ........................
    ........................
    ................O.......
    ...............O.O......
    ...............O.O......
    ................O.......
    ...............OO.......
    ...............OO.......
    ...............OO.......

:methuselah Any small pattern that stabilizes only after a long time. Term coined by Conway. Examples include rabbits, acorn, the R-pentomino, blom, Iwona, Justyna and Lidka. See also ark.

:Mickey Mouse (p1) A name proposed by Mark Niemiec for the following still life:

    .OO....OO.
    O..O..O..O
    O..OOOO..O
    .OO....OO.
    ...OOOO...
    ...O..O...
    ....OO....

:middleweight emulator = MW emulator

:middleweight spaceship = MWSS

:middleweight volcano = MW volcano

:mini pressure cooker (p3) Found by Robert Wainwright before June 1972. Compare pressure cooker.

    .....O.....
    ....O.O....
    ....O.O....
    ...OO.OO...
    O.O.....O.O
    OO.O.O.O.OO
    ...O...O...
    ...O.O.O...
    ....O.O....
    .....O.....

:M.I.P. value The maximum population divided by the initial population for an unstable pattern. For example, the R-pentomino has an M.I.P. value of 63.8, since its maximum population is 319. The term is no longer in use.

:MIT oscillator = cuphook

:MMM breeder See breeder.

:MMS breeder See breeder.

:mod The smallest number of generations it takes for an oscillator or spaceship to reappear in its original form, possibly subject to some rotation or reflection. The mod may be equal to the period, but it may also be a quarter of the period (for oscillators that rotate 90 degrees every quarter period) or half the period (for other oscillators which rotate 180 degrees every half period, and also for flippers).

:mold (p4) Found by Achim Flammenkamp in 1988, but not widely known until Dean Hickerson rediscovered it (and named it) in August 1989. Compare with jam. In terms of its minimum population of 12 it ties with mazing as the smallest p4 oscillator. But in terms of its 6x6 bounding box it wins outright. In fact, of all oscillators that fit in a 6x7 box it is the only one with period greater than 2.

    ...OO.
    ..O..O
    O..O.O
    ....O.
    O.OO..
    .O....

:monogram (p4) Found by Dean Hickerson, August 1989.

    OO...OO
    .O.O.O.
    .OO.OO.
    .O.O.O.
    OO...OO

:moose antlers (p1)

    OO.....OO
    O.......O
    .OOO.OOO.
    ...O.O...
    ....O....

:mosquito See mosquito1, mosquito2. mosquito3, mosquito4 and mosquito5.

:mosquito1 A breeder constructed by Nick Gotts in September 1998. The original version had an initial population of 103, which was then the smallest for any known pattern with superlinear growth (beating the record previously held by Jaws). This was reduced to 97 by Stephen Silver the following month, but was then almost immediately superseded by mosquito2.

Mosquito1 consists of the classic puffer train plus four LWSS and four MWSS (mostly in predecessor form, to keep the population down). Once it gets going it produces a new block-laying switch engine (plus a lot of junk) every 280 generations. It is therefore an MMS breeder, albeit a messy one.

:mosquito2 A breeder constructed by Nick Gotts in October 1998. Its initial population of 85 was for a couple of hours the smallest for any known pattern with superlinear growth, but was then beaten by mosquito3.

Mosquito2 is very like mosquito1, but uses two fewer MWSS and one more LWSS.

:mosquito3 A breeder constructed by Nick Gotts in October 1998. Its initial population of 75 was at the time the smallest for any known pattern with superlinear growth, but was beaten a few days later by mosquito4.

Mosquito3 has one less LWSS than mosquito2. It is somewhat different from the earlier mosquitoes in that the switch engines it makes are glider-producing rather than block-laying.

:mosquito4 A slightly improved version of mosquito3 which Stephen Silver produced in October 1998 making use of another discovery of Nick Gotts (September 1997): an 8-cell pattern that evolves into a LWSS plus some junk. Mosquito4 is a breeder with an initial population of 73, at the time the smallest for any known pattern with superlinear growth, but superseded a few days later by mosquito5.

:mosquito5 A slightly improved version of mosquito4 which Nick Gotts produced in October 1998. The improvement is of a similar nature to the improvement of mosquito4 over mosquito3. Mosquito5 is a breeder with an initial population of 71. At the time, this was the smallest population for any known pattern with superlinear growth, but it has since been superseded by teeth, catacryst and metacatacryst.

:mould = mold

:moving sawtooth A sawtooth such that no cell is ON for more than a finite number generations. David Bell has constructed patterns of this type, with a c/2 front end and a c/3 back end.

:MSM breeder See breeder.

:multi-state Life = colorized Life

:multum in parvo (stabilizes at time 3933) A methuselah found by Charles Corderman, but not as long-lasting as his acorn.

    ...OOO
    ..O..O
    .O....
    O.....

:muttering moat Any oscillator whose rotor consists of a closed chain of cells each of which is adjacent to exactly two other rotor cells. Compare babbling brook. Examples include the bipole, the blinker, the clock, the cuphook, the Gray counter, the quad, the scrubber, the skewed quad and the p2 snake pit. The following diagram shows a p2 example (by Dean Hickerson, May 1993) with a larger rotor. See ring of fire for a very large one.

    OO.....
    O.O.OO.
    .....O.
    .O..O..
    ..O....
    ..O.O.O
    .....OO

:MW emulator (p4) Found by Robert Wainwright in June 1980. See also emulator and filter.

    .......O.......
    ..OO.O...O.OO..
    ..O.........O..
    ...OO.....OO...
    OOO..OOOOO..OOO
    O..O.......O..O
    .OO.........OO.

:MWSS (c/2 orthogonally, p4) A middleweight spaceship, the third most common spaceship. Found by Conway in 1970. See also LWSS and HWSS.

    ...O..
    .O...O
    O.....
    O....O
    OOOOO.

:MWSS emulator = MW emulator

:MWSS out of the blue The following reaction, found by Peter Rott in November 1997, in which a LWSS passing by a p46 oscillator creates a MWSS travelling in the opposite direction. Together with some reactions found by Dieter Leithner, and a LWSS-turning reaction which Rott had found in November 1993 (but which was not widely known until Paul Callahan rediscovered it in June 1994) this can be used to prove that there exist gliderless guns for LWSS, MWSS and HWSS for every period that is a multiple of 46.

    O..O.................................
    ....O................................
    O...O................................
    .OOOO................................
    .....................................
    .....................................
    .....................................
    .....................................
    .....................................
    ...................OO..............OO
    ..................OO...............OO
    ...................OOOOO.............
    ..OO................OOOO.............
    ..OO.....O...........................
    ........OOO.........OOOO.............
    .......O.O.O.......OOOOO.............
    ........O..O......OO...............OO
    ........OOO........OO..............OO
    .........O...........................
    .....................................
    .....................................
    .....................................
    .....................................
    ..O.......O..........................
    .....................................
    OOO.......OOO........................
    .OO.OO.OO.OO.........................
    ..OOO...OOO..........................
    ...O.....O...........................
    .....................................
    .....................................
    .....................................
    .....................................
    .....................................
    .....................................
    .....................................
    .....................................
    .....................................
    .....................................
    ..OO.....OO..........................
    ..OO.....OO..........................

:MW volcano (p5) Found by Dean Hickerson in April 1992.

    ......O......
    ....O...O....
    .............
    ...O.....O...
    .OOO.OOO.OOO.
    O...OO.OO...O
    O.OOO.O.OOOO.
    .O...........
    ...O.O.O.OO.O
    ..OO.OOO.O.OO
    ...O.O..O....
    ...O..OO.....
    ..OO.........

:My Experience with B-heptominos in Oscillators An article by Dave Buckingham (October 1996) that describes his discovery of Herschel conduits, including sufficient (indeed ample) stable conduits to enable, for the first time, the construction of period n oscillators - and true period n guns - for every sufficiently large integer n. (See Herschel loop and emu.)

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