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A seed is a constellation that when triggered (normally hit by a glider) evolves into a target object, possibly with some extra junk.

Seed constellations are commonly used in self-constructing circuitry. For example, to create a faraway target object to start construction of a new copy of a construction arm at a safe distance, it is often useful to use a seed for a complex spaceship or wickstretcher -- something that can be stopped when it reaches its destination by following it with a faster spaceship or wick burning reaction.

One-glider seeds, or "1G seeds", are particularly useful in slow salvo construction because the constellation can be built up incrementally, with changes made one glider at a time. When it is complete it can be triggered by the final glider in the recipe. Triggering a seed will usually create several precisely synchronized gliders that then co-operate to construct the target object, similar to a standard glider synthesis.[1]

Common one-glider seeds

Many common active regions have common objects that are one-glider seeds. Here is a list:

x = 44, y = 8, rule = B3/S23 obo7bobo7bobo7bobo7bobo$b2o8b2o8b2o8b2o8b2o$bo9bo9bo9bo9bo2$b2o8b2o8b2o8b2o8b2o$b2o7bo2bo6bobo7bobo7bo2bo$11b2o8bo8b2o8bo2bo$41b2o! #C [[ THUMBSIZE 2 THEME 6 GRID GRIDMAJOR 0 SUPPRESS THUMBLAUNCH ]] #C [[ AUTOSTART GPS 5 LOOP 17 T 0 PAUSE 0.6 T 4 PAUSE 0.4 T 6 PAUSE 0.7 T 12 PAUSE 0.2 ]]
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RLE: here Plaintext: here

The reason that so many objects are one-glider seeds for a pi-sequence is because when a glider hits a line of two cells in a still life in a certain way, the way that the glider reacts almost always produces a pentaplet grandparent of the pi-heptomino after four generations, as well as some cells behind it.[2] For a block, beehive, boat (in one orientation), ship (in one orientation), and pond, the excess cells turn out to be sparks, so a clean pi-sequence is produced. The only common one-glider seed for a pi-sequence that does not produce the pi-this way is a blinker, which does not actually produce a pi-heptomino but instead produces a twelve-cell cluster with the same great-grandparent (hence the term pi-sequence rather than pi-heptomino).


Many spaceships and some other difficult-to-construct objects have activation stages that require many gliders coming at once from multiple directions. For uses in self-constructing circuitry, simply firing all of the gliders at once in a synchronized manner is impractical. For this reason, for the activation stage, the activation stage uses a series of turners and splitters that create all of the necessary synchronized gliders from only one initial glider that requires no synchronization.

See also


  1. Goldtiger997 (July 7, 2020). One Glider Seeds (discussion thread) at the forums
  2. Entity Valkyrie 2 (October 4, 2020). One Glider Seeds (discussion thread) at the forums

External links