SlowSilver Demonoid

SlowSilver Demonoid
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Pattern type	Spaceship
Number of cells	15329
Direction	Diagonal
Period	309174 (mod: 154587)
Speed	55c/309174 | 55c/309174
Heat	Unknown
Kinetic symmetry	n/e
Discovered by	Evin
Year of discovery	2026
Rules Outer-totalistic rules B3/S23 only # of rules 20 = 1 Isotropic rules B3/S23 only
Pattern files Macrocell SlowSilver2A.mc

The SlowSilver Demonoid is a demonoid spaceship. The "Mark 1" SlowSilver was completed by Evin in February 9, 2026, based on an idea from Adam P. Goucher in 2023. Initial design work on the spaceship was done by Adam P. Goucher, Dave Greene, and Evin.

History

Shortly after the Mark 1 design, iNoMed halved the bounding box and period by minimising the empty space in the tape, yielding the "SlowSilver 1.1" design with a speed of 55c/965358d. Subsequently, Evin modified the destruction mechanism to produce the smaller "SlowSilver 2A" design with a minimum population of 14017. 6 hours later, iNoMed compressed it into a 55c/926870 spaceship. The following day, Evin constructed the even smaller "SlowSilver 2C" by running pslmake with a higher beamwidth; later that day, iNoMed, I6_I6 and Evin reduced it to 55c/533870. An hour later, Evin posted the much smaller version 2H with speed 55c/309174 by using 6 construction units at a time instead of just 3.

Design

The SlowSilver Demonoid is based on the design of the 0hd Demonoid. The distinguishing feature of the "SlowSilver" design is the use of constructor units based on Callahan G-to-Hs attached to NW31 converters, called "CGNW31" for short. Adam P. Goucher's original proposal used the Silver reflector, which led to the name. However, Evin subsequently proposed using an edge-shooter based on the Callahan G-to-H, resulting in a design more similar to the original demonoids. Similarly to the 0hd Demonoid, the SlowSilver Demonoid uses multiple construction units to insert gliders onto a single-channel lane. This allows using single-channel recipes with a minimum spacing of 15 ticks, while only requiring one construction unit to be built per cycle. As with other demonoids, the spaceship is composed of two identical halves with a stream of gliders between them, and is glide-reflective.

In order to be a spaceship, the trailing construction unit must be destroyed every cycle. In the 1, 1.1, and 2A versions, the destruction mechanism was inspired by a mechanism proposed by Simon Ekström for an older demonoid design. To trigger the destruction, a backwards glider travels through the demonoid on a transparent lane to interact with an active reaction in the last construction unit. This produced a cheaper design compared to the offset trigger design used in other demonoids.

See also

• QuickSilver Demonoid