Add info on seeds
[cellular-automata.git] / seeds / README.md
1 Seeds
2 =====
3
4 https://en.wikipedia.org/wiki/Seeds_(cellular_automaton)
5
6 > Seeds is a cellular automaton in the same family as the Game of Life,
7 > initially investigated by Brian Silverman[1][2] and named by Mirek
8 > Wójtowicz.[1][3] It consists of infinite two-dimensional grid of cells, each
9 > of which may be in one of two states: on or off. Each cell is considered to
10 > have eight neighbors (Moore neighborhood), as in Life. In each time step, a
11 > cell turns on or is "born" if it was off or "dead" but had exactly two
12 > neighbors that were on; all other cells turn off. Thus, in the notation
13 > describing the family of cellular automata containing Life, it is described
14 > by the rule B2/S.[1]
15 >
16 > In Game of Life terminology, a pattern in which all cells that were on turn
17 > off at each step is called a phoenix. All patterns in Seeds have this form.
18 > Even though all live cells are constantly dying, the small birth requirement
19 > of two cells means that nearly every pattern in Seeds explodes into a chaotic
20 > mess that grows to cover the entire universe. Thus, in Wolfram's
21 > classification of cellular automata, it is a Class III automaton, in which
22 > nearly all patterns evolve chaotically.[1]
23 >
24 > However, some patterns are known to behave in a more controlled fashion,
25 > repeating the same shape either in the same position of the grid (an
26 > oscillator) or translated some number of grid units after several steps (a
27 > spaceship). More complex rake and puffer patterns are known which move like
28 > spaceships leaving trails of oscillators or other spaceships behind them.
29 > Most of these patterns move at a speed of 1 cell per time step (the so-called
30 > speed of light, or c/1)[4] including three commonly seen spaceships with four
31 > on cells each, but slower-moving patterns are also known. A collection of
32 > patterns for the Seeds rule collected by Jason Summers includes patterns
33 > found by Stephen Wright, Mirek Wójtowicz, Noam Elkies, Mark Niemiec, Peter
34 > Naszvadi, and David Eppstein.[5]
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