:**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..

:**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.

:**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 6×6 bounding box it wins outright. In fact, of all
oscillators that fit in a 6×7 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.

:**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.

:**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.)