A gliderless gun is a spaceship gun that doesn't involve gliders. The most famous example is the period-44 MWSS gun, based on a glider gun by David Buckingham (see P44 pi-heptomino hassler). Additionally, Dietrich Leithner created many gliderless spaceship guns, particularly those based on the twin bees shuttle.
There is no strict definition for what constitutes a gliderless gun. For example, solutions based on Herschel tracks may produce gliders, even though they aren't utilised in the reaction. Some increasingly strict conditions might include:
- a synthesis of the output spaceship that is not a form of glider synthesis
- a core gun engine that does not output gliders
- the absence of any reactions from the gun that would output gliders
- the absence of a glider-shaped cluster at any point in the operation of the gun
- the absence of any rectangular bounding box containing a glider-shaped polyplet, at any point in the operation of the gun
Below is a LWSS gun that fits the first four of the above criteria. The fifth criterion would be much harder to fulfill. For example, a glider-shaped polyplet is visible in the T=0 form of the gun, although it is not surrounded by OFF cells. Similar regions can be found in other phases. Many more regions can be found that, if isolated, would converge to a glider within a few ticks. But since this isolation never occurs in the actual evolution of the pattern, the gun counts as gliderless by any reasonable definition of the term.
|An example of a gliderless LWSS gun based on Tanner's p46|
(click above to open LifeViewer)