Introduction | Bibliography

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:B = B-heptomino

:B29 (c/4 diagonally, p4) The following spaceship, found by Hartmut Holzwart in September 2004.

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

:B-52 bomber The following p104 double-barrelled glider gun. It uses a B-heptomino and emits one glider every 52 generations. It was found by Noam Elkies in March 1996, except that Elkies used blockers instead of molds, the improvement being found by David Bell later the same month.

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

:babbling brook Any oscillator whose rotor consists of a string of cells each of which is adjacent to exactly two other rotor cells, except for the endpoints which are adjacent to only one other rotor cell. Compare muttering moat. Examples include the beacon, the great on-off, the light bulb and the spark coil. The following less trivial example (by Dean Hickerson, August 1997) is the only one known with more than four cells in its rotor. It is p4 and has a 6-cell rotor.

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

:backrake Another term for a backwards rake. A p8 example by Jason Summers is shown below. See total aperiodic for a p12 example.

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

:backward glider A glider which moves at least partly in the opposite direction to the puffer(s) or spaceship(s) under consideration.

:baker (c p4 fuse) A fuse by Keith McClelland.

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

:baker's dozen (p12) A loaf hassled by two blocks and two caterers. The original form (using p4 and p6 oscillators to do the hassling) was found by Robert Wainwright in August 1989.

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

:bakery (p1) A common formation of two bi-loaves.

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

:barberpole Any p2 oscillator in the infinite sequence bipole, tripole, quadpole, pentapole, hexapole, heptapole ... (It wasn't my idea to suddenly change from Latin to Greek.) This sequence of oscillators was found by the MIT group in 1970. The term is also used (usually in the form "barber pole") to describe other extensible sections of oscillators or spaceships, especially those (usually of period 2) in which all generations look alike except for a translation and/or rotation/reflection.

:barberpole intersection = quad

:barber's pole = barberpole

:barge (p1)

    .O..
    O.O.
    .O.O
    ..O.

:basic shuttle = queen bee shuttle

:beacon (p2) The third most common oscillator. Found by Conway, March 1970.

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

:beacon maker (c p8 fuse)

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

:beehive (p1) The second most common still life.

    .OO.
    O..O
    .OO.

:beehive and dock (p1)

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

:beehive on big table = beehive and dock

:beehive pusher = hivenudger

:beehive with tail (p1)

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

:belly spark The spark of a MWSS or HWSS other than the tail spark.

:bent keys (p3) Found by Dean Hickerson, August 1989. See also odd keys and short keys.

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

:B-heptomino (stabilizes at time 148) This is a very common pattern. It often arises with the cell at top left shifted one space to the left, which does not affect the subsequent evolution. B-heptominoes acquired particular importance in 1996 due to Dave Buckingham's work on B tracks - see in particular My Experience with B-heptominos in Oscillators.

    O.OO
    OOO.
    .O..

:B-heptomino shuttle = twin bees shuttle

:bi-block (p1) The smallest pseudo still life.

    OO.OO
    OO.OO

:bi-boat = boat-tie

:biclock The following pure glider generator consisting of two clocks.

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

:big beacon = figure-8

:big fish = HWSS

:big glider (c/4 diagonally, p4) This was found by Dean Hickerson in December 1989 and was the first known diagonal spaceship other than the glider.

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

:big S (p1)

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

:big table = dock

:billiard table configuration Any oscillator in which the rotor is enclosed within the stator. Examples include airforce, cauldron, clock II, Hertz oscillator, negentropy, pinwheel, pressure cooker and scrubber.

:bi-loaf This term has been used in at least three different senses. A bi-loaf can be half a bakery:

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

or it can be the following much less common still life:

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

or the following pure glider generator:

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

:bipole (p2) The barberpole of length 2.

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

:bi-pond (p1)

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

:bi-ship = ship-tie

:bit A live cell.

:biting off more than they can chew (p3) Found by Peter Raynham, July 1972.

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

:Black&White = Immigration

:blasting cap The pi-heptomino (after the shape at generation 1). A term used at MIT and still occasionally encountered.

:blinker (p2) The smallest and most common oscillator. Found by Conway, March 1970.

    OOO

:blinker puffer Any puffer whose output is blinkers. However, the term is particularly used for p8 c/2 puffers. The first such blinker puffer was found by Robert Wainwright in 1984, and was unexpectedly simple:

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

Since then many more blinker puffers have been found. The following one was found by David Bell in 1992 when he was trying to extend an x66:

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

The importance of this larger blinker puffer (and others like it), is that the engine which produces the blinker output is only p4. The blinker row produced by the puffer can easily be ignited, and burns cleanly with a speed of 2c/3. When the burning catches up to the engine, it causes a phase change in the puffer. This fact allows p8 blinker puffers to be used to construct rakes of all periods which are large multiples of four.

:blinkers bit pole (p2) Found by Robert Wainwright, June 1977.

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

:blinker ship A growing spaceship in which the wick consists of a line of blinkers. An example by Paul Schick based on his Schick engine is shown below. Here the front part is p12 and moves at c/2, while the back part is p26 and moves at 6c/13. Every 156 generations 13 blinkers are created and 12 are destroyed, so the wick becomes one blinker longer.

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

:block (p1) The most common still life.

    OO
    OO

:blockade (p1) A common formation of four blocks. The final form of lumps of muck.

    OO.....................
    OO.....................
    .......................
    .......................
    .OO.................OO.
    .OO.................OO.
    .......................
    .......................
    .....................OO
    .....................OO

:block and dock (p1)

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

:block and glider (stabilizes at time 106)

    OO..
    O.O.
    ..OO

:blocker (p8) Found by Robert Wainwright. See also filter.

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

:block on big table = block and dock

:block on table (p1)

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

:block pusher A pattern emitting streams of gliders which can repeatedly push a block further away. This can be used as part of a sliding block memory.

The following pattern, in which three gliders push a block one cell diagonally, is an example of how a block pusher works.

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

:blom (stabilizes at time 23314) The following methuselah, found by Dean Hickerson in July 2002.

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

:blonk A block or a blinker. This term is mainly used in the context of sparse Life and was coined by Rich Schroeppel in September 1992.

:blonker (p6) The following oscillator, found by Nicolay Beluchenko in April 2004.

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

:boat (p1) The only 5-cell still life.

    OO.
    O.O
    .O.

:boat-bit A binary digit represented by the presence of a boat next to a snake (or other suitable object, such as an aircraft carrier). The bit can be toggled by a glider travelling along a certain path. A correctly timed glider on a crossing path can detect whether the transition was from 1 to 0 (in which case the crossing glider is deleted) or from 0 to 1 (in which case it passes unharmed). Three gliders therefore suffice for a non-destructive read. The mechanisms involved are shown in the diagram below. Here the bit is shown in state 0. It is about to be set to 1 and then switched back to 0 again. The first crossing glider will survive, but the second will be destroyed. (In January 1997 David Bell found a method of reading the bit while setting it to 0. A MWSS is fired at the boat-bit. If it is already 0 then the MWSS passes unharmed, but if it is 1 then the boat and the MWSS are destroyed and, with the help of an eater1, converted into a glider which travels back along exactly the same path that is used by the gliders that toggle the boat-bit.)

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

:boat maker (c p4 fuse)

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

:boat on boat = boat-tie

:boat-ship-tie = ship tie boat

:boatstretcher See tubstretcher.

:boat-tie (p1) A 10-cell still life consisting of two boats placed tip-to-tip. The name is a pun on "bow tie".

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

:boojum reflector (p1) Dave Greene's name for the following reflector which he found in April 2001, and which is currently the smallest known stable reflector.

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

:bookend The following induction coil. It is generation 1 of century.

    ..OO
    O..O
    OOO.

:bookends (p1)

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

:boss (p4) Found by Dave Buckingham, 1972.

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

:bottle (p8) Found by Achim Flammenkamp in August 1994. The name is a back-formation from ship in a bottle.

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

:bounding box The smallest rectangular array of cells that contains the whole of a given pattern. For oscillators and guns this usually is meant to include all phases of the pattern, but excludes, in the case of guns, the outgoing stream(s).

:bow tie = boat-tie

:brain (c/3 orthogonally, p3) Found by David Bell, May 1992.

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

:breeder Any pattern whose population grows at a quadratic rate, although it is usual to exclude spacefillers. It is easy to see that this is the fastest possible growth rate.

The term is also sometimes used to mean specifically the breeder created by Bill Gosper's group at MIT, which was the first known pattern exhibiting superlinear growth.

There are four basic types of breeder, known as MMM, MMS, MSM and SMM (where M=moving and S=stationary). Typically an MMM breeder is a rake puffer, an MMS breeder is a puffer producing puffers which produce stationary objects (still lifes and/or oscillators), an MSM breeder is a gun puffer and an SMM breeder is a rake gun. There are, however, less obvious variants of these types. The original breeder was of type MSM (a p64 puffer puffing p30 glider guns).

The known breeder with the smallest initial population is the metacatacryst.

:bridge A term used in naming certain still lifes (and the stator part of certain oscillators). It indicates that the object consists of two smaller objects joined edge to edge, as in snake bridge snake.

:broken lines A pattern constructed by Dean Hickerson in May 2005 which produces complex broken lines of gliders and blocks.

:broth = soup

:BTC = billiard table configuration

:B track A track for B-heptominoes. The term is more-or-less synonymous with Herschel track, since a B-heptomino becomes a Herschel plus a block in twenty generations.

:buckaroo A queen bee shuttle stabilized at one end by an eater in such a way that it can turn a glider, as shown below. This was found by Dave Buckingham in the 1970s. The name is due to Bill Gosper.

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

:bullet heptomino Generation 1 of the T-tetromino.

    .O.
    OOO
    OOO

:bun The following induction coil. By itself this is a common predecessor of the honey farm. See also cis-mirrored R-bee.

    .OO.
    O..O
    .OOO

:bunnies (stabilizes at time 17332) This is a parent of rabbits and was found independently by Robert Wainwright and Andrew Trevorrow.

    O.....O.
    ..O...O.
    ..O..O.O
    .O.O....

:burloaf = loaf

:burloaferimeter (p7) Found by Dave Buckingham in 1972. See also airforce.

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

:bushing That part of the stator of an oscillator which is adjacent to the rotor. Compare casing.

:butterfly The following pattern, or the formation of two beehives that it evolves into after 33 generations. (Compare teardrop, where the beehives are five cells closer together.)

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

:by flops (p2) Found by Robert Wainwright.

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

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