A pattern is referred to as Spartan if it can be easily constructed with a slow salvo, or with a similarly restricted universal construction toolkit such as the paired 90-degree slow salvos used in the original Gemini spaceship.
What is implied by easily is quite subjective and has changed over the years as technology has improved.
A pattern is referred to as Spartan if it can be built with slmake in any orientation. This subsumes all previous definitions, as it includes a much larger set of basic still lifes (including the beehive with tail featured in the syringe) and period-2 oscillators (found by the automated HoneySearch program, inspired by Paul Chapman's Glue). In addition to these, slmake has also been provided with a set of human-assisted 'bespoke' constructions of various important objects:
- Eater 2
- 45-degree MWSS-to-G
- The eater bridge eater still life featured in the 135-degree MWSS-to-G, F116 and Fx176 conduits.
Inter alia, this means that the dependent form of the syringe (recovery time 90 by using the similarly constructible Lx200) can easily be constructed -- a prerequisite for single channel self-constructing circuitry.
The original definition of Spartan was put forward by Dave Greene, who defined it to be a 'constellation of well-separated still lifes, each of 7 of fewer bits'. The pond was later added to this list as it is particularly easy to synthesise, and is occasionally used as a catalyst and as a construction intermediate.
Spartan still lifes
These still-lifes are commonly considered Spartan: block, tub, boat, hive, ship, loaf, eater 1, long boat, pond. Snake and aircraft carrier are also small enough that they might be considered Spartan, but they are generally not included because in most conduits they can be replaced by an eater 1, which is easier to construct. Similarly, barge can be normally replaced by a boat. On the other hand, long boat is important not as a conduit component, but as the simplest color-changing 180-degree turner, and similarly an aircraft carrier is a very simple colour-changing "0-degree turner".
Paul Chapman's Glue search program was upgraded to allow period-2 intermediates, such as blinkers, in slow salvo constructions. This increases the branching factor of the search tree to enable more efficient constructions, and has the side effect of concomitantly widening the definition of 'Spartan' to include a few period-2 oscillators:
These oscillators are regarded as Spartan: blinker, beacon, toad. Spartan oscillators are normally considered only as an intermediate synthesis product in p2 slow salvo construction. Pulsar is technically Spartan too, but it hasn't appeared useful enough to bother developing p3 or p6 slow salvo synthesis.
In 2012 a few other still lifes particularly useful in signal circuitry, such as tub-with-tails and dead spark coils, were shown to be constructible in all orientations using slow salvos. These objects have sometimes been referred to as "near-Spartan" or "Spartan++", but in practice they were not used in larger circuit construction recipes until after the advent of slmake.
- Adam P. Goucher. Re: Stable glider reflector (discussion thread) at the ConwayLife.com forums
- Sergey Petrov. Re: Thread For Your Accidental Discoveries (discussion thread) at the ConwayLife.com forums
- Spartan at the Life Lexicon