:p1 Period 1, i.e., stable. In the context of logic circuitry, this tends to mean that a mechanism is constructed from Herschel conduits that contain only still lifes as catalysts. In the context of slow glider construction, a P1 slow salvo is one in which there are no constraints on the parity of gliders in the salvo, because the intermediate targets are all stable constellations. (The usual alternative is a "P2 slow salvo", where the relative timing between adjacent gliders can be increased arbitrarily, but only by multiples of two ticks.)
:p104 gun A glider gun with period 104, found by Noam Elkies on 21 March 1996. It is based on an R-pentomino shuttle reaction.
:p11 bumper (p11) A periodic colour-preserving glider reflector with a minimum repeat time of 44 ticks. Unlike the p5 through p8 cases where Noam Elkies' domino-spark based reflectors are available, no small period-22 colour-changing reflector is known. A stable Snark reflector can be substituted for any bumper. This changes the timing of the output glider, which can be useful for rephasing periodic glider streams.
In practice this reflector is not useful with input streams below period 121, because lower-period bumpers can be used to reflect all smaller multiples of 11 for which the bumper reaction can be made to work.
:p130 shuttle A shuttle found in March 2004 by David Eppstein, which originally needed several period 5 oscillators for support. David Bell found a reaction between two of the shuttles to produce a p130 glider gun. On 18 November 2017 Tanner Jacobi found that the stable sidesnagger can be used to support the shuttle instead, and this is shown here.
:p144 gun A glider gun with true period 144. The first one was found by Bill Gosper in July 1994. For a full description and pattern see factory.
:p14 gun A glider gun which emits a period 14 glider stream. This is the smallest possible period for any stream, so such a gun is of great interest. There is no known true-period p14 glider gun, and finding a small direct example is well beyond current search algorithms' abilities. However, pseudo-period p14 guns have been created by injecting gliders into a higher period glider stream. The first pseudo p14 gun was built by Dieter Leithner in 1995. Smaller pseudo p14 guns have since been constructed, but they are still much too large to show here. The essential mechanism used by them is demonstrated in GIG.
:p15 bouncer Noam Elkies' colour-changing glider reflector, with Karel's p15 providing the necessary domino spark. Compare to the colour-preserving Snark. The minimum repeat time is 30 ticks.
:p15 bumper A periodic colour-preserving glider reflector with Karel's p15 providing the necessary spark. The minimum repeat time is 45 ticks. For an equivalent colour-changing periodic glider reflector see p15 bouncer. A stable Snark reflector can be substituted for any bumper. This changes the timing of the output glider, which can be useful for rephasing periodic glider streams.
:p15 reflector An ambiguous term that may refer to PD-pair reflector, p15 bouncer, or the more recently discovered p15 bumper.
:p184 gun A true period 184 double-barrelled glider gun found by Dave Buckingham in July 1996. The engine in this gun is a Herschel descendant. Unlike previous glider guns, the reaction flips on a diagonal so that both gliders travel in the same direction.
:p1 megacell (p1 circuitry) A metacell constructed by Adam P. Goucher in 2008, capable of being programmed to emulate any Moore neighborhood rule, including isotropic and anisotropic non-totalistic rules. It fits in a 32768 by 32768 bounding box, with the resulting metacell grid at 45 degrees to the underlying Life grid. Like the OTCA metapixel, it includes a large "pixel" area so that the state of the megacell can easily be seen even at extremely small-scale zoom levels.
:p1 telegraph (p1 circuitry) A variant of Jason Summers' telegraph pattern, constructed in 2010 by Adam P. Goucher using only stable circuitry. A single incoming glider produces the entire ten-part composite lightspeed signal that restores the beehive-chain lightspeed wire to its original position. The signal is detected at the other end of the telegraph and converted back into a single output signal. This simplification came at the cost of a much slower transmission speed, one bit per 91080 ticks. In this mechanism, sending the entire ten-part signal constitutes a '1' bit, and not sending the signal means '0'. See also high-bandwidth telegraph.
:p22 gun A true period 22 glider gun constructed by David Eppstein in August 2000, using two interacting copies of a p22 oscillator found earlier the same day by Jason Summers.
:p246 gun A true period glider gun with period 246, discovered by Dave Buckingham in June 1996. The 180-degree mod-123 symmetry of its bookend-based engine makes it trivial to modify it into a double-barrelled gun. Its single-barreled form is shown below.
:p24 gun A glider gun with true period 24. The first one was found by Noam Elkies in June 1997. It uses three p4 oscillators to hassle a pair of traffic lights. One of the oscillators was very large and custom-made. Shown below is a much smaller version built by Jason Summers and Karel Suhajda in December 2002, using the same mechanism but with a smaller oscillator:
:p256 gun A true period 256 four-barrelled glider gun found by Dave Buckingham in September 1995. It uses four R64 conduits to make the second smallest known Herschel loop (after the Simkin glider gun). The p256 gun was an early "teaser" from Dave Buckingham before he released his full Herschel technology.
:p29 pentadecathlon hassler A hassler where two copies of a period 29 oscillator (which is itself a pre-pulsar hassler) change the period of a pentadecathlon.
:p30 gun A glider gun with true period 30. The first one, found by Bill Gosper in November 1970 (see Gosper glider gun), was also the first gun found of any period. All known p30 glider guns are made from two or more interacting queen bee shuttles. Paul Callahan found 30 different ways that three queen bee shuttles can react to form a period 30 glider gun. One of the most interesting of these is shown below in which the gliders emerge in an unexpected direction.
:p30 shuttle = queen bee shuttle
:p36 gun A glider gun with true period 36. The first one was found by Jason Summers in 2004. Shown below is a smaller version using improvements by Adam P. Goucher and Scot Ellison:
:p3 bumper A variant of Tanner Jacobi's bumper found by Arie Paap in April 2018. Two forms of the period 3 oscillator catalyst are shown below.
For bounding box optimization purposes, it's also possible to replace the eater1 in a p3, p6 or p9 bumper with another period 3 oscillator, saving one row along the south edge at the cost of a higher population.
The repeat time for all these variants is 36 ticks, as shown.
:p44 gun A glider gun with a true period of 44. The first one was found by Dave Buckingham in April 1992. It uses two interacting copies of an oscillator which he also found. In 1996 he found a gun which only used one copy of the oscillator. Paul Callahan improved it in 1997, resulting in the gun shown below:
:p44 MWSS gun A gun discovered by Dieter Leithner in April 1997, in a somewhat larger form. This was the smallest known gliderless gun and smallest known MWSS gun until the construction in 2017 of the gun shown under gliderless, based on Tanner's p46.
The p44 MWSS gun is based on a p44 oscillator discovered by Dave Buckingham in early 1992, shown here in an improved form found in January 2005 by Jason Summers using a new p4 sparker by Nicolay Beluchenko. A glider shape appears in this gun for three consecutive generations, but always as part of a larger cluster, so even a purist would regard this gun as gliderless.