Introduction | Bibliography

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:natural Occurring often in random patterns. There is no precise measure of naturalness, since the most useful definition of "random" in this context is open to debate. Nonetheless, it is clear that objects such as blocks, blinkers, beehives and gliders are very natural, while eater2s, darts, guns, etc., are not.

:natural Heisenburp (p46) A twin bees shuttle pair arrangement found by Brice Due in 2006. A glider passes through the reaction area of the shuttle pair completely unaffected. However, a Heisenburp effect causes a second glider to be created "out of the blue", following behind the first at a 2hd offset.

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

:ND read = non-destructive read

:negative spaceship A type of signal travelling through a periodic agar such as zebra stripes. The leading edge of the signal removes the agar, and the trailing edge rebuilds the agar some time later. The distance between the two edges is sometimes adjustable, as shown in lightspeed bubble. The central part of the "spaceship" may consist of dying sparks or even simple empty space.

Below is a sample period-5 negative spaceship, found by Hartmut Holzwart in March 2007, in a small stabilized section of zebra stripes agar:

    .O..O..O..O..O..O..O..O..O..O..O..O..O..O..O..O..O..O..O.
    .OOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO.
    .........................................................
    .OOOOOOOOOOOOOOOOOOOOOOOOOOOOO..OOO..OOOOOOOOOOOOOOOOOOO.
    O..............................OO...OO..................O
    .OOOOOOOOOOOOOOOOOOOOOOOO..OOO...OO...OOOO..OOOOOOOOOOOO.
    ..........................OO...............OO............
    .OOOOOOOOOOOOOOOOOOOOOOOO..OOO...OO.....OO...OO..OOOOOOO.
    O..............................OO...O.OO........OO......O
    .OOOOOOOOOOOOOOOOOOOOOOOO..OOO..OOO...OO.....OO...OOOOOO.
    ..........................OO............OO.OO............
    .OOOOOOOOOOOOOOOOOOOOOOOO...OOOOO..........OO.....OOOOOO.
    O............................O...............OO.OO......O
    .OOOOOOOOOOOOOOOOOOOOOOOO.....O.........O.......OO..OOOO.
    ..........................O.O......O...O..........OO.....
    .OOOOOOOOOOOOOOOOOOOOOOOO...O.O.OOOOO......O.......OOOOO.
    O..............................OOO...O......O...........O
    .OOOOOOOOOOOOOOOOOOOOOOOO...O.O.OOOOO......O.......OOOOO.
    ..........................O.O......O...O..........OO.....
    .OOOOOOOOOOOOOOOOOOOOOOOO.....O.........O.......OO..OOOO.
    O............................O...............OO.OO......O
    .OOOOOOOOOOOOOOOOOOOOOOOO...OOOOO..........OO.....OOOOOO.
    ..........................OO............OO.OO............
    .OOOOOOOOOOOOOOOOOOOOOOOO..OOO..OOO...OO.....OO...OOOOOO.
    O..............................OO...O.OO........OO......O
    .OOOOOOOOOOOOOOOOOOOOOOOO..OOO...OO.....OO...OO..OOOOOOO.
    ..........................OO...............OO............
    .OOOOOOOOOOOOOOOOOOOOOOOO..OOO...OO...OOOO..OOOOOOOOOOOO.
    O..............................OO...OO..................O
    .OOOOOOOOOOOOOOOOOOOOOOOOOOOOO..OOO..OOOOOOOOOOOOOOOOOOO.
    .........................................................
    .OOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO.
    .O..O..O..O..O..O..O..O..O..O..O..O..O..O..O..O..O..O..O.

The "spaceship" travels to the left at the speed of light, so it will eventually reach the edge of any finite patch and destroy itself and its supporting agar.

:negentropy (p2) Compare Hertz oscillator.

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

:neighbour Any of the eight cells adjacent to a given cell. A cell is therefore not considered to be a neighbour of itself, although the neighbourhood used in Life does in fact include this cell (see cellular automaton).

:new five (p3) Found by Dean Hickerson, January 1990.

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

:new gun (p46) An old name for the period 46 glider gun show below. This was found by Bill Gosper in 1971, and was the second basic glider gun found (after the Gosper glider gun). It produces a period 46 glider stream.

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

A number of other ways of constructing a gun from two twin bees shuttles have since been found. See edge shooter for one of these, and see also p46 gun.

:Noah's ark The following diagonal puffer consisting of two switch engines. This was found by Charles Corderman in 1971. The name comes from the variety of objects it leaves behind: blocks, blinkers, beehives, loaves, gliders, ships, boats, long boats, beacons and block on tables.

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

See also ark.

:n-omino Any polyomino with exactly n cells.

:non-destructive read A type of test reaction in memory cell circuitry, where the information in the memory cell is unchanged and can be read again to produce the same result. One simple type of non-destructive read reaction is a signal sent to a permanent switch. Memory cells with destructive read reactions are generally simpler and more commonly used.

:nonfiller = space nonfiller

:non-monotonic A spaceship is said to be non-monotonic if its leading edge falls back in some generations. The first example (shown below) was found by Hartmut Holzwart in August 1992. This is p4 and travels at c/4. In April 1994, Holzwart found examples of p3 spaceships with this property, and this is clearly the smallest possible period. Another non-monotonic spaceship is the weekender.

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

:nonomino switch engine predecessor This is the unique nonomino (a polyomino having 9 cells) whose evolution results in a switch engine, and the smallest polyomino to do so.

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

Charles Corderman may have found this object in 1971 while exhaustively investigating the fate of all the small polyominoes. Records indicate that he found the switch engine while investigating the decominoes (polyominoes having 10 cells). However, there do not appear to be decominoes which result in a clean switch engine. If Corderman was examining polyominoes in order of size, then this smaller predecessor should have been found first in any case.

:non-spark Something that looks like a spark, but isn't. An OWSS produces one of these instead of a belly spark, and is destroyed by it.

:non-standard spaceship Any spaceship other than a glider, LWSS, MWSS or HWSS.

:non-trivial A non-trivial period-N oscillator contains at least one cell that oscillates at the full period. In other words, it is not made up solely of separate oscillators with smaller periods. Usually it includes a spark or other reaction that would not occur if all lower-period subpatterns were separated from each other, but some exceptions are given under trivial. See also omniperiodic.

:novelty generator A pattern that appears to have an unknown fate due to complex feedback loops, for example involving waves of gliders shuttling between perpendicular rakes. Novelty generator patterns fall short of counting as chaotic growth, since the rakes continue to be predictable, and much of their ash generally remains stable.

It has not been proven conclusively that any particular pattern is in fact an infinite novelty generator, since it is always possible that periodicity will spontaneously arise if the simulation is continued far enough. In fact this happens quite regularly. But conversely, it has not been proven that periodicity must spontaneously arise for all such patterns. Bill Gosper, Nick Gotts and others have done extensive experiments along these lines using Golly.

:NW31 One of the most common stable edge shooters. This Herschel-to-glider converter suppresses the junk ordinarily left behind by an evolving Herschel while allowing both the first natural glider and second natural glider to escape on transparent lanes:

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

The edge shooter output at the top has no additional clearance, so its use in creating convoys is limited: it can only add gliders on the outermost lanes of an existing glider salvo. Like the beehive version of SW-2, either output can be used to build logical OR gates, where multiple input signal paths are merged onto the same output path.

The complete name for this converter is "NW31T120", where 31 is the output glider lane number. In the above orientation, lane numbers get bigger toward the upper right and smaller toward the lower left (and may easily be negative).

The T120 timing measurement means that a canonical NW glider placed on lane 31 at time T=120, at (+31, +0) relative to the input Herschel, would in theory reach the exact same spacetime locations as the converter's output glider does.

Most converters are not edge shooters and their output lanes are not transparent, so they usually have catalysts that would interfere with this theoretically equivalent glider. This is the case for the optional third glider output created by the lower eater1 catalyst: the upper eater1 overlaps its lane. For the alternate block catalyst suppressing this glider output, see transparent lane.

:NW31T120 = NW31

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