:vacuum Empty space. That is, space containing only dead cells.
:Venetian blinds The p2 agar obtained by using the pattern O..O to tile the plane.
:very long house The following induction coil.
.OOOOO. O..O..O OO...OO |
:volatility The volatility of an oscillator is the size (in cells) of its rotor divided by the sum of the sizes of its rotor and its stator. In other words, it is the proportion of cells involved in the oscillator which actually oscillate. For many periods there are known oscillators with volatility 1, see for example Achim's p16he barberpole of length 3.
OO.... O.O... ...... ..O.O. .....O ....OO |
:tritoad (p3) Found by Dave Buckingham, October 1977.
:true Opposite of pseudo. A gun emitting a period n stream of spaceships (or rakes) is said to be a true period n gun if its mechanism oscillates with period n. (The same distinction between true and pseudo also exists for puffers.) True period n guns are known to exist for all periods greater than 61 (see My Experience with B-heptominos in Oscillators), but only a few smaller periods have been achieved, namely 22, 24, 30, 36, 44, 46, 48, 50, 54, 55, 56 and 60. (Credits for these small period guns are: p30, p46 and p60 by Bill Gosper in 1970-1971, p44 by Dave Buckingham in 1992, p50 by Dean Hickerson in 1996, p24 and p48 by Noam Elkies in 1997, p54 and p56 by Dieter Leithner in early 1998, p55 by Stephen Silver in late 1998, p22 by David Eppstein in 2000 and p36 by Jason Summers in 2004.)
The following diagram shows the p22 gun (David Eppstein, August 2000, using two copies of a p22 oscillator found earlier the same day by Jason Summers).