⚠️ Warning: This is a draft ⚠️

This means it might contain formatting issues, incorrect code, conceptual problems, or other severe issues.

If you want to help to improve and eventually enable this page, please fork RosettaGit's repository and open a merge request on GitHub.

The purpose of this task is to create a version of an [[Elementary cellular automaton]] whose number of cells is only limited by the memory size of the computer.

To be precise, consider the state of the automaton to be made of an infinite number of cells, but with a bounded [[wp:support (mathematics)|support]]. In other words, to describe the state of the automaton, you need a finite number of adjacent cells, along with their individual state, and you then consider that the individual state of each of all other cells is the negation of the closest individual cell among the previously defined finite number of cells.

Examples:

```
1        ->   ..., 0, 0,      1,      0, 0, ...
0, 1     ->   ..., 1, 1,   0, 1,      0, 0, ...
1, 0, 1  ->   ..., 0, 0,   1, 0, 1,   0, 0, ...

```

More complex methods can be imagined, provided it is possible to somehow encode the infinite sections. But for this task we will stick to this simple version.

C++

```
#include <iostream>
#include <iomanip>
#include <string>

class oo {
public:
void evolve( int l, int rule ) {
std::string    cells = "O";
std::cout << " Rule #" << rule << ":\n";
for( int x = 0; x < l; x++ ) {
std::cout << std::setw( 40 + ( static_cast<int>( cells.length() ) >> 1 ) ) << cells << "\n";
step( cells, rule );
}
}
private:
void step( std::string& cells, int rule ) {
int bin;
std::string newCells;
for( size_t i = 0; i < cells.length() - 2; i++ ) {
bin = 0;
for( size_t n = i, b = 2; n < i + 3; n++, b >>= 1 ) {
bin += ( ( cells[n] == 'O' ? 1 : 0 ) << b );
}
newCells.append( 1, rule & ( 1 << bin ) ? 'O' : '.' );
}
cells = newCells;
}
void addNoCells( std::string& s ) {
char l = s.at( 0 ) == 'O' ? '.' : 'O',
r = s.at( s.length() - 1 ) == 'O' ? '.' : 'O';
s = l + s + r;
s = l + s + r;
}
};
int main( int argc, char* argv[] ) {
oo o;
o.evolve( 35, 90 );
std::cout << "\n";
return 0;
}

```

{{out}}

```
Rule #90:                                                    Rule #30:
..O..                                                        ..O..
..O.O..                                                      ..OOO..
..O...O..                                                    ..OO..O..
..O.O.O.O..                                                  ..OO.OOOO..
..O.......O..                                                ..OO..O...O..
..O.O.....O.O..                                              ..OO.OOOO.OOO..
..O...O...O...O..                                            ..OO..O....O..O..
..O.O.O.O.O.O.O.O..                                          ..OO.OOOO..OOOOOO..
..O...............O..                                        ..OO..O...OOO.....O..
..O.O.............O.O..                                      ..OO.OOOO.OO..O...OOO..
..O...O...........O...O..                                    ..OO..O....O.OOOO.OO..O..
..O.O.O.O.........O.O.O.O..                                  ..OO.OOOO..OO.O....O.OOOO..
..O.......O.......O.......O..                                ..OO..O...OOO..OO..OO.O...O..
..O.O.....O.O.....O.O.....O.O..                              ..OO.OOOO.OO..OOO.OOO..OO.OOO..
..O...O...O...O...O...O...O...O..                            ..OO..O....O.OOO...O..OOO..O..O..
..O.O.O.O.O.O.O.O.O.O.O.O.O.O.O.O..                          ..OO.OOOO..OO.O..O.OOOOO..OOOOOOO..
..O...............................O..                        ..OO..O...OOO..OOOO.O....OOO......O..
..O.O.............................O.O..                      ..OO.OOOO.OO..OOO....OO..OO..O....OOO..
..O...O...........................O...O..                    ..OO..O....O.OOO..O..OO.OOO.OOOO..OO..O..
..O.O.O.O.........................O.O.O.O..                  ..OO.OOOO..OO.O..OOOOOO..O...O...OOO.OOOO..
..O.......O.......................O.......O..                ..OO..O...OOO..OOOO.....OOOO.OOO.OO...O...O..
..O.O.....O.O.....................O.O.....O.O..              ..OO.OOOO.OO..OOO...O...OO....O...O.O.OOO.OOO..
..O...O...O...O...................O...O...O...O..            ..OO..O....O.OOO..O.OOO.OO.O..OOO.OO.O.O...O..O..
..O.O.O.O.O.O.O.O.................O.O.O.O.O.O.O.O..          ..OO.OOOO..OO.O..OOO.O...O..OOOO...O..O.OO.OOOOOO..
..O...............O...............O...............O..        ..OO..O...OOO..OOOO...OO.OOOOO...O.OOOOO.O..O.....O..

```

D

{{trans|Python}}

```import std.stdio, std.array, std.range, std.typecons, std.string, std.conv,
std.algorithm;
alias R = replicate;

void main() {
enum nLines = 25;
enum notCell = (in char c) pure => (c == '1') ? "0" : "1";

foreach (immutable rule; [90, 30]) {
writeln("\nRule: ", rule);
immutable ruleBits = "%08b".format(rule).retro.text;
const neighs2next = 8.iota
.map!(n => tuple("%03b".format(n), [ruleBits[n]]))
.assocArray;

string C = "1";
foreach (immutable i; 0 .. nLines) {
writefln("%2d: %s%s", i, " ".R(nLines - i), C.tr("01", ".#"));
C = notCell(C[0]).R(2) ~ C ~ notCell(C[\$ - 1]).R(2);
C = iota(1, C.length - 1)
.map!(i => neighs2next[C[i - 1 .. i + 2]])
.join;
}
}
}
```

The output is the same as the Python entry.

Elixir

{{works with|Elixir|1.3}} {{trans|Ruby}}

```
defmodule Elementary_cellular_automaton do
def infinite(cell, rule, times) do
each(cell, rule_pattern(rule), times)
end

defp each(_, _, 0), do: :ok
defp each(cells, rules, times) do
IO.write String.duplicate(" ", times)
IO.puts String.replace(cells, "0", ".") |> String.replace("1", "#")
c = not_cell(String.first(cells)) <> cells <> not_cell(String.last(cells))
next_cells = Enum.map_join(0..String.length(cells)+1, fn i ->
Map.get(rules, String.slice(c, i, 3))
end)
each(next_cells, rules, times-1)
end

defp not_cell("0"), do: "11"
defp not_cell("1"), do: "00"

defp rule_pattern(rule) do
list = Integer.to_string(rule, 2) |> String.pad_leading(8, "0")
|> String.codepoints |> Enum.reverse
Enum.map(0..7, fn i -> Integer.to_string(i, 2) |> String.pad_leading(3, "0") end)
|> Enum.zip(list) |> Map.new
end
end

Enum.each([18, 30], fn rule ->
IO.puts "\nRule : #{rule}"
Elementary_cellular_automaton.infinite("1", rule, 25)
end)
```

{{out}}

```
Rule : 18
#
#.#
#...#
#.#.#.#
#.......#
#.#.....#.#
#...#...#...#
#.#.#.#.#.#.#.#
#...............#
#.#.............#.#
#...#...........#...#
#.#.#.#.........#.#.#.#
#.......#.......#.......#
#.#.....#.#.....#.#.....#.#
#...#...#...#...#...#...#...#
#.#.#.#.#.#.#.#.#.#.#.#.#.#.#.#
#...............................#
#.#.............................#.#
#...#...........................#...#
#.#.#.#.........................#.#.#.#
#.......#.......................#.......#
#.#.....#.#.....................#.#.....#.#
#...#...#...#...................#...#...#...#
#.#.#.#.#.#.#.#.................#.#.#.#.#.#.#.#
#...............#...............#...............#

Rule : 30
#
###
##..#
##.####
##..#...#
##.####.###
##..#....#..#
##.####..######
##..#...###.....#
##.####.##..#...###
##..#....#.####.##..#
##.####..##.#....#.####
##..#...###..##..##.#...#
##.####.##..###.###..##.###
##..#....#.###...#..###..#..#
##.####..##.#..#.#####..#######
##..#...###..####.#....###......#
##.####.##..###....##..##..#....###
##..#....#.###..#..##.###.####..##..#
##.####..##.#..######..#...#...###.####
##..#...###..####.....####.###.##...#...#
##.####.##..###...#...##....#...#.#.###.###
##..#....#.###..#.###.##.#..###.##.#.#...#..#
##.####..##.#..###.#...#..####...#..#.##.######
##..#...###..####...##.#####...#.#####.#..#.....#

```

Go

{{trans|C++}}

```package main

import (
"fmt"
"strings"
)

func btoi(b bool) int {
if b {
return 1
}
return 0
}

func evolve(l, rule int) {
fmt.Printf(" Rule #%d:\n", rule)
cells := "O"
for x := 0; x < l; x++ {
width := 40 + (len(cells) >> 1)
fmt.Printf("%*s\n", width, cells)
cells = step(cells, rule)
}
}

func step(cells string, rule int) string {
newCells := new(strings.Builder)
for i := 0; i < len(cells)-2; i++ {
bin := 0
b := uint(2)
for n := i; n < i+3; n++ {
bin += btoi(cells[n] == 'O') << b
b >>= 1
}
a := '.'
if rule&(1<<uint(bin)) != 0 {
a = 'O'
}
newCells.WriteRune(a)
}
return newCells.String()
}

func addNoCells(cells string) string {
l, r := "O", "O"
if cells[0] == 'O' {
l = "."
}
if cells[len(cells)-1] == 'O' {
r = "."
}
cells = l + cells + r
cells = l + cells + r
return cells
}

func main() {
for _, r := range []int{90, 30} {
evolve(25, r)
fmt.Println()
}
}
```

{{out}}

```
Rule #90:
..O..
..O.O..
..O...O..
..O.O.O.O..
..O.......O..
..O.O.....O.O..
..O...O...O...O..
..O.O.O.O.O.O.O.O..
..O...............O..
..O.O.............O.O..
..O...O...........O...O..
..O.O.O.O.........O.O.O.O..
..O.......O.......O.......O..
..O.O.....O.O.....O.O.....O.O..
..O...O...O...O...O...O...O...O..
..O.O.O.O.O.O.O.O.O.O.O.O.O.O.O.O..
..O...............................O..
..O.O.............................O.O..
..O...O...........................O...O..
..O.O.O.O.........................O.O.O.O..
..O.......O.......................O.......O..
..O.O.....O.O.....................O.O.....O.O..
..O...O...O...O...................O...O...O...O..
..O.O.O.O.O.O.O.O.................O.O.O.O.O.O.O.O..
..O...............O...............O...............O..

Rule #30:
..O..
..OOO..
..OO..O..
..OO.OOOO..
..OO..O...O..
..OO.OOOO.OOO..
..OO..O....O..O..
..OO.OOOO..OOOOOO..
..OO..O...OOO.....O..
..OO.OOOO.OO..O...OOO..
..OO..O....O.OOOO.OO..O..
..OO.OOOO..OO.O....O.OOOO..
..OO..O...OOO..OO..OO.O...O..
..OO.OOOO.OO..OOO.OOO..OO.OOO..
..OO..O....O.OOO...O..OOO..O..O..
..OO.OOOO..OO.O..O.OOOOO..OOOOOOO..
..OO..O...OOO..OOOO.O....OOO......O..
..OO.OOOO.OO..OOO....OO..OO..O....OOO..
..OO..O....O.OOO..O..OO.OOO.OOOO..OO..O..
..OO.OOOO..OO.O..OOOOOO..O...O...OOO.OOOO..
..OO..O...OOO..OOOO.....OOOO.OOO.OO...O...O..
..OO.OOOO.OO..OOO...O...OO....O...O.O.OOO.OOO..
..OO..O....O.OOO..O.OOO.OO.O..OOO.OO.O.O...O..O..
..OO.OOOO..OO.O..OOO.O...O..OOOO...O..O.OO.OOOOOO..
..OO..O...OOO..OOOO...OO.OOOOO...O.OOOOO.O..O.....O..

```

Infinite lists are natural in Haskell, however the task forces us to deal with lists that are infinite in both directions. These structures could be efficiently implemented as a ''zipper lists''. Moreover, zipper lists are instances of magic `Comonad` class, which gives beautifull implementation of cellular automata.

This solution is kinda involved, but it is guaranteed to be total and correct by type checker.

First we provide the datatype, the viewer and constructor:

```{-# LANGUAGE DeriveFunctor #-}

import Data.InfList (InfList (..), (+++))
import qualified Data.InfList as Inf

data Cells a = Cells (InfList a) a (InfList a) deriving Functor

view n (Cells l x r) = reverse (Inf.take n l) ++ [x] ++ (Inf.take n r)

fromList []     = fromList [0]
fromList (x:xs) = let zeros = Inf.repeat 0
in Cells zeros x (xs +++ zeros)
```

In order to run the CA on the domain we make it an instance of `Comonad` class. Running the CA turns to be just an iterative comonadic ''extension'' of the rule:

```instance Comonad Cells where
extract (Cells _ x _) = x
duplicate x = Cells (rewind left x) x (rewind right x)
where
rewind dir = Inf.iterate dir . dir
right (Cells l x (r ::: rs)) = Cells (x ::: l) r rs
left  (Cells (l ::: ls) x r) = Cells ls l (x ::: r)

runCA rule = iterate (=>> step)
where step (Cells (l ::: _) x (r ::: _)) = rule l x r
```

Following is the rule definition and I/O routine:

```rule n l x r = n `div` (2^(4*l + 2*x + r)) `mod` 2

displayCA n w rule init = mapM_ putStrLn \$ take n result
where result = fmap display . view w <\$> runCA rule init
display 0 = ' '
display _ = '*'
```

{{Out}}

```λ> displayCA 30 20 (rule 90) (fromList [1])
*
* *
*   *
* * * *
*       *
* *     * *
*   *   *   *
* * * * * * * *
*               *
* *             * *
*   *           *   *
* * * *         * * * *
*       *       *       *
* *     * *     * *     * *
*   *   *   *   *   *   *   *
* * * * * * * * * * * * * * * *
*                               *
* *                             * *
*   *                           *   *
* * * *                         * * * *
*       *                       *       *
*     * *                     * *     *
*   *   *                   *   *   *
* * * * * *                 * * * * * *
*               *
* *             * *
*   *           *   *
* * * *         * * * *
*       *       *       *       *       *
*     * *     * *     * *     * *     *
```

J

Implementation note: edges are complement of the first and last represented cell, which we define as 1 for the case of an empty numeric list. (So we can represent an infinite space of 0s but not an infinite space of 1s.)

We actually only extend our edges by 9 positions (which is more than sufficient), and then trim everything up to the first change from each edge (so the result from a rule which results in all 1s will be silently converted to an empty all 0s result).

Note however that this means that positions in the result are not anchored to positions in the argument. They might correspond or they might be "off by one" position.

Implementation:

```ext9=: (9#1-{.!.1),],9#1-{:!.1
trim=: |.@(}.~ ] i. 1-{.)^:2
next=: trim@(((8\$2) #: [) {~ 2 #. 1 - [: |: |.~"1 0&_1 0 1@]) ext9
```

In other words, a wrapped version of the [[Elementary_cellular_automaton#J|original implementation]].

example use:

```   ' *'{~90 next^:(i.9) 1
*
* *
*   *
* * * *
*       *
* *     * *
*   *   *   *
* * * * * * * *
*               *
```

Looks like a [[Sierpinski_triangle|Sierpinski triangle]]

Julia

{{trans|Python}}

```function ecainfinite(cells, rule, n)
notcell(cell) = (cell == '1') ? '0' : '1'
rulebits = reverse(string(rule, base = 2, pad = 8))
neighbors2next = Dict(string(n - 1, base=2, pad=3) => rulebits[n] for n in 1:8)
ret = String[]
for i in 1:n
push!(ret, cells)
cells = notcell(cells[1])^2 * cells * notcell(cells[end])^2 # Extend/pad ends
cells = join([neighbors2next[cells[i:i+2]] for i in 1:length(cells)-2], "")
end
ret
end

function testinfcells(lines::Integer)
for rule in [90, 30]
println("\nRule: \$rule (\$(string(rule, base = 2, pad = 8)))")
s = ecainfinite("1", rule, lines)
for i in 1:lines
println("\$i: ", " "^(lines - i), replace(replace(s[i], "0" => "."), "1" => "#"))
end
end
end

testinfcells(25)

```

{{out}}

```
Rule: 90 (01011010)
1:                         #
2:                        #.#
3:                       #...#
4:                      #.#.#.#
5:                     #.......#
6:                    #.#.....#.#
7:                   #...#...#...#
8:                  #.#.#.#.#.#.#.#
9:                 #...............#
10:                #.#.............#.#
11:               #...#...........#...#
12:              #.#.#.#.........#.#.#.#
13:             #.......#.......#.......#
14:            #.#.....#.#.....#.#.....#.#
15:           #...#...#...#...#...#...#...#
16:          #.#.#.#.#.#.#.#.#.#.#.#.#.#.#.#
17:         #...............................#
18:        #.#.............................#.#
19:       #...#...........................#...#
20:      #.#.#.#.........................#.#.#.#
21:     #.......#.......................#.......#
22:    #.#.....#.#.....................#.#.....#.#
23:   #...#...#...#...................#...#...#...#
24:  #.#.#.#.#.#.#.#.................#.#.#.#.#.#.#.#
25: #...............#...............#...............#

Rule: 30 (00011110)
1:                         #
2:                        ###
3:                       ##..#
4:                      ##.####
5:                     ##..#...#
6:                    ##.####.###
7:                   ##..#....#..#
8:                  ##.####..######
9:                 ##..#...###.....#
10:                ##.####.##..#...###
11:               ##..#....#.####.##..#
12:              ##.####..##.#....#.####
13:             ##..#...###..##..##.#...#
14:            ##.####.##..###.###..##.###
15:           ##..#....#.###...#..###..#..#
16:          ##.####..##.#..#.#####..#######
17:         ##..#...###..####.#....###......#
18:        ##.####.##..###....##..##..#....###
19:       ##..#....#.###..#..##.###.####..##..#
20:      ##.####..##.#..######..#...#...###.####
21:     ##..#...###..####.....####.###.##...#...#
22:    ##.####.##..###...#...##....#...#.#.###.###
23:   ##..#....#.###..#.###.##.#..###.##.#.#...#..#
24:  ##.####..##.#..###.#...#..####...#..#.##.######
25: ##..#...###..####...##.#####...#.#####.#..#.....#

```

Kotlin

{{trans|C++}}

```// version 1.1.51

fun evolve(l: Int, rule: Int) {
println(" Rule #\$rule:")
var cells = StringBuilder("*")
for (x in 0 until l) {
val width = 40 + (cells.length shr 1)
cells = step(cells, rule)
}
}

fun step(cells: StringBuilder, rule: Int): StringBuilder {
val newCells = StringBuilder()
for (i in 0 until cells.length - 2) {
var bin = 0
var b = 2
for (n in i until i + 3) {
bin += (if (cells[n] == '*') 1 else 0) shl b
b = b shr 1
}
val a = if ((rule and (1 shl bin)) != 0) '*' else '.'
newCells.append(a)
}
return newCells
}

fun addNoCells(s: StringBuilder) {
val l = if (s[0] == '*') '.' else '*'
val r = if (s[s.length - 1] == '*') '.' else '*'
repeat(2) {
s.insert(0, l)
s.append(r)
}
}

fun main(args: Array<String>) {
evolve(35, 90)
println()
}
```

{{out}}

```
Rule #90:
..*..
..*.*..
..*...*..
..*.*.*.*..
..*.......*..
..*.*.....*.*..
..*...*...*...*..
..*.*.*.*.*.*.*.*..
..*...............*..
..*.*.............*.*..
..*...*...........*...*..
..*.*.*.*.........*.*.*.*..
..*.......*.......*.......*..
..*.*.....*.*.....*.*.....*.*..
..*...*...*...*...*...*...*...*..
..*.*.*.*.*.*.*.*.*.*.*.*.*.*.*.*..
..*...............................*..
..*.*.............................*.*..
..*...*...........................*...*..
..*.*.*.*.........................*.*.*.*..
..*.......*.......................*.......*..
..*.*.....*.*.....................*.*.....*.*..
..*...*...*...*...................*...*...*...*..
..*.*.*.*.*.*.*.*.................*.*.*.*.*.*.*.*..
..*...............*...............*...............*..
..*.*.............*.*.............*.*.............*.*..
..*...*...........*...*...........*...*...........*...*..
..*.*.*.*.........*.*.*.*.........*.*.*.*.........*.*.*.*..
..*.......*.......*.......*.......*.......*.......*.......*..
..*.*.....*.*.....*.*.....*.*.....*.*.....*.*.....*.*.....*.*..
..*...*...*...*...*...*...*...*...*...*...*...*...*...*...*...*..
..*.*.*.*.*.*.*.*.*.*.*.*.*.*.*.*.*.*.*.*.*.*.*.*.*.*.*.*.*.*.*.*..
..*...............................................................*..
..*.*.............................................................*.*..
..*...*...........................................................*...*..

```

Perl

The edges of a pattern is implicitly repeating. The code will try to lineup output by padding up to 40 spaces to the left, but since the cells keep expanding, that has to end somewhere.

```sub evolve {
my (\$rule, \$pattern) = @_;
my \$offset = 0;

while (1) {
my (\$l, \$r, \$st);
\$pattern =~ s/^((.)\g2*)/\$2\$2/ and \$l = \$2, \$offset -= length(\$2);
\$pattern =~ s/(.)\g1*\$/\$1\$1/   and \$r = \$1;

\$st = \$pattern;

\$pattern =~ tr/01/.#/;
printf "%5d| %s%s\n", \$offset, ' ' x (40 + \$offset), \$pattern;

\$pattern = join '', map(1 & (\$rule>>oct "0b\$_"),
\$l x 3,
map(substr(\$st, \$_, 3), 0 .. length(\$st)-3),
\$r x 3);
}
}

evolve(90, "010");
```

{{out}}

```
-1|                                        ..#..
-2|                                       ..#.#..
-3|                                      ..#...#..
-4|                                     ..#.#.#.#..
-5|                                    ..#.......#..
-6|                                   ..#.#.....#.#..
-7|                                  ..#...#...#...#..
-8|                                 ..#.#.#.#.#.#.#.#..
-9|                                ..#...............#..
-10|                               ..#.#.............#.#..
-11|                              ..#...#...........#...#..
-12|                             ..#.#.#.#.........#.#.#.#..
-13|                            ..#.......#.......#.......#..
---(infinite more lines snipped)---

```

Perl 6

This version, while it is ''capable'' of working with infinite length cellular automata, makes the assumption that any cells which have not been explicitly examined are in a 'null' state, neither '0' or '1'. Further it makes the assumption that a null cell, on being examined, initially contains nothing (░). Otherwise it would take infinite time to calculate every row and would be exceptionally boring to watch.

Based heavily on the code from the [[One-dimensional_cellular_automata#Perl_6|One-dimensional cellular automata]] task. Example uses rule 90 (Sierpinski triangle).

```class Automaton {
has \$.rule;
has @.cells;
has @.code = \$!rule.fmt('%08b').flip.comb».Int;

method gist { @!cells.map({+\$_ ?? '▲' !! '░'}).join }

method succ {
self.new: :\$!rule, :@!code, :cells(
' ',
|@!code[
4 «*« @!cells.rotate(-1)
»+« 2 «*« @!cells
»+«       @!cells.rotate(1)
],
' '
)
}
}

my Automaton \$a .= new: :rule(90), :cells(flat '010'.comb);

# display the first 20 rows
say \$a++ for ^20;

# then calculate the other infinite number of rows, (may take a while)
\$a++ for ^Inf;
```

{{out}}

```░▲░
░▲░▲░
░▲░░░▲░
░▲░▲░▲░▲░
░▲░░░░░░░▲░
░▲░▲░░░░░▲░▲░
░▲░░░▲░░░▲░░░▲░
░▲░▲░▲░▲░▲░▲░▲░▲░
░▲░░░░░░░░░░░░░░░▲░
░▲░▲░░░░░░░░░░░░░▲░▲░
░▲░░░▲░░░░░░░░░░░▲░░░▲░
░▲░▲░▲░▲░░░░░░░░░▲░▲░▲░▲░
░▲░░░░░░░▲░░░░░░░▲░░░░░░░▲░
░▲░▲░░░░░▲░▲░░░░░▲░▲░░░░░▲░▲░
░▲░░░▲░░░▲░░░▲░░░▲░░░▲░░░▲░░░▲░
░▲░▲░▲░▲░▲░▲░▲░▲░▲░▲░▲░▲░▲░▲░▲░▲░
░▲░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░▲░
░▲░▲░░░░░░░░░░░░░░░░░░░░░░░░░░░░░▲░▲░
░▲░░░▲░░░░░░░░░░░░░░░░░░░░░░░░░░░▲░░░▲░
░▲░▲░▲░▲░░░░░░░░░░░░░░░░░░░░░░░░░▲░▲░▲░▲░
^C

```

Phix

Uses 0-expansion either side

```string s = ".#.",
t=s, r = "........"
integer rule = 18, k, l = length(s), w = 0
for i=1 to 8 do
r[i] = iff(mod(rule,2)?'#':'.')
rule = floor(rule/2)
end for
for i=0 to 25 do
?repeat(' ',floor((55-length(s))/2))&s
for j=1 to l do
k = (s[iff(j=1?l:j-1)]='#')*4
+ (s[          j   ]='#')*2
+ (s[iff(j=l?1:j+1)]='#')+1
t[j] = r[k]
end for
if t[1]='#' then t = '.'&t end if
if t[\$]='#' then t = t&'.' end if
l = length(t)
s = t
end for
```

{{out}}

```
"                          .#."
"                         .#.#."
"                        .#...#."
"                       .#.#.#.#."
"                      .#.......#."
"                     .#.#.....#.#."
"                    .#...#...#...#."
"                   .#.#.#.#.#.#.#.#."
"                  .#...............#."
"                 .#.#.............#.#."
"                .#...#...........#...#."
"               .#.#.#.#.........#.#.#.#."
"              .#.......#.......#.......#."
"             .#.#.....#.#.....#.#.....#.#."
"            .#...#...#...#...#...#...#...#."
"           .#.#.#.#.#.#.#.#.#.#.#.#.#.#.#.#."
"          .#...............................#."
"         .#.#.............................#.#."
"        .#...#...........................#...#."
"       .#.#.#.#.........................#.#.#.#."
"      .#.......#.......................#.......#."
"     .#.#.....#.#.....................#.#.....#.#."
"    .#...#...#...#...................#...#...#...#."
"   .#.#.#.#.#.#.#.#.................#.#.#.#.#.#.#.#."
"  .#...............#...............#...............#."
" .#.#.............#.#.............#.#.............#.#."

```

Python

Infinite generator but only print 25 lines of each rule.

```def _notcell(c):
return '0' if c == '1' else '1'

def eca_infinite(cells, rule):
lencells = len(cells)
rulebits = '{0:08b}'.format(rule)
neighbours2next = {'{0:03b}'.format(n):rulebits[::-1][n] for n in range(8)}
c = cells
while True:
yield c
c = _notcell(c[0])*2 + c + _notcell(c[-1])*2    # Extend and pad the ends

c = ''.join(neighbours2next[c[i-1:i+2]] for i in range(1,len(c) - 1))
#yield c[1:-1]

if __name__ == '__main__':
lines = 25
for rule in (90, 30):
print('\nRule: %i' % rule)
for i, c in zip(range(lines), eca_infinite('1', rule)):
print('%2i: %s%s' % (i, ' '*(lines - i), c.replace('0', '.').replace('1', '#')))
```

{{out}}

```Rule: 90
0:                          #
1:                         #.#
2:                        #...#
3:                       #.#.#.#
4:                      #.......#
5:                     #.#.....#.#
6:                    #...#...#...#
7:                   #.#.#.#.#.#.#.#
8:                  #...............#
9:                 #.#.............#.#
10:                #...#...........#...#
11:               #.#.#.#.........#.#.#.#
12:              #.......#.......#.......#
13:             #.#.....#.#.....#.#.....#.#
14:            #...#...#...#...#...#...#...#
15:           #.#.#.#.#.#.#.#.#.#.#.#.#.#.#.#
16:          #...............................#
17:         #.#.............................#.#
18:        #...#...........................#...#
19:       #.#.#.#.........................#.#.#.#
20:      #.......#.......................#.......#
21:     #.#.....#.#.....................#.#.....#.#
22:    #...#...#...#...................#...#...#...#
23:   #.#.#.#.#.#.#.#.................#.#.#.#.#.#.#.#
24:  #...............#...............#...............#

Rule: 30
0:                          #
1:                         ###
2:                        ##..#
3:                       ##.####
4:                      ##..#...#
5:                     ##.####.###
6:                    ##..#....#..#
7:                   ##.####..######
8:                  ##..#...###.....#
9:                 ##.####.##..#...###
10:                ##..#....#.####.##..#
11:               ##.####..##.#....#.####
12:              ##..#...###..##..##.#...#
13:             ##.####.##..###.###..##.###
14:            ##..#....#.###...#..###..#..#
15:           ##.####..##.#..#.#####..#######
16:          ##..#...###..####.#....###......#
17:         ##.####.##..###....##..##..#....###
18:        ##..#....#.###..#..##.###.####..##..#
19:       ##.####..##.#..######..#...#...###.####
20:      ##..#...###..####.....####.###.##...#...#
21:     ##.####.##..###...#...##....#...#.#.###.###
22:    ##..#....#.###..#.###.##.#..###.##.#.#...#..#
23:   ##.####..##.#..###.#...#..####...#..#.##.######
24:  ##..#...###..####...##.#####...#.#####.#..#.....#
```

Racket

Uses solution to [[Elementary cellular automaton]] saved in file "Elementary_cellular_automata.rkt"

```#lang racket
; below is the code from the parent task
(require "Elementary_cellular_automata.rkt")
(require racket/fixnum)

(define (wrap-rule-infinite v-in vl-1 offset)
(define l-bit-set? (bitwise-bit-set? (fxvector-ref v-in 0) usable-bits/fixnum-1))
(define r-bit-set? (bitwise-bit-set? (fxvector-ref v-in vl-1) 0))
;; if we need to extend left offset is reduced by 1
(define l-pad-words (if l-bit-set? 1 0))
(define r-pad-words (if r-bit-set? 1 0))
(cond
[(fx= 0 new-words) (values v-in vl-1 offset)] ; nothing changes
[else
(define offset- (if l-bit-set? (fx- offset 1) offset))
(define l-sequence (if l-bit-set? (in-value 0) (in-sequences)))
(define vl-1+ (fx+ vl-1 (fx+ l-pad-words r-pad-words)))
(define v-out
(for/fxvector
#:length (fx+ vl-1+ 1) #:fill 0 ; right padding
([f (in-sequences l-sequence (in-fxvector v-in))])
f))
(values v-out vl-1+ offset-)]))

(module+ main
(define ng/90/infinite (CA-next-generation 90 #:wrap-rule wrap-rule-infinite))
(for/fold ([v (fxvector #b10000000000000000000)]
[o 1]) ; start by pushing output right by one
([step (in-range 40)])
(show-automaton v #:step step #:push-right o)
(newline)
(ng/90/infinite v o)))
```

{{out}}

```[         0] ..............................000000000010000000000000000000
[         1] ..............................000000000101000000000000000000
[         2] ..............................000000001000100000000000000000
[         3] ..............................000000010101010000000000000000
[         4] ..............................000000100000001000000000000000
[         5] ..............................000001010000010100000000000000
[         6] ..............................000010001000100010000000000000
[         7] ..............................000101010101010101000000000000
[         8] ..............................001000000000000000100000000000
[         9] ..............................010100000000000001010000000000
[        10] ..............................100010000000000010001000000000
[        11] 000000000000000000000000000001010101000000000101010100000000
[        12] 000000000000000000000000000010000000100000001000000010000000
[        13] 000000000000000000000000000101000001010000010100000101000000
[        14] 000000000000000000000000001000100010001000100010001000100000
[        15] 000000000000000000000000010101010101010101010101010101010000
[        16] 000000000000000000000000100000000000000000000000000000001000
[        17] 000000000000000000000001010000000000000000000000000000010100
[        18] 000000000000000000000010001000000000000000000000000000100010
[        19] 000000000000000000000101010100000000000000000000000001010101
[        20] 000000000000000000001000000010000000000000000000000010000000100000000000000000000000000000
[        21] 000000000000000000010100000101000000000000000000000101000001010000000000000000000000000000
[        22] 000000000000000000100010001000100000000000000000001000100010001000000000000000000000000000
[        23] 000000000000000001010101010101010000000000000000010101010101010100000000000000000000000000
[        24] 000000000000000010000000000000001000000000000000100000000000000010000000000000000000000000
[        25] 000000000000000101000000000000010100000000000001010000000000000101000000000000000000000000
[        26] 000000000000001000100000000000100010000000000010001000000000001000100000000000000000000000
[        27] 000000000000010101010000000001010101000000000101010100000000010101010000000000000000000000
[        28] 000000000000100000001000000010000000100000001000000010000000100000001000000000000000000000
[        29] 000000000001010000010100000101000001010000010100000101000001010000010100000000000000000000
[        30] 000000000010001000100010001000100010001000100010001000100010001000100010000000000000000000
[        31] 000000000101010101010101010101010101010101010101010101010101010101010101000000000000000000
[        32] 000000001000000000000000000000000000000000000000000000000000000000000000100000000000000000
[        33] 000000010100000000000000000000000000000000000000000000000000000000000001010000000000000000
[        34] 000000100010000000000000000000000000000000000000000000000000000000000010001000000000000000
[        35] 000001010101000000000000000000000000000000000000000000000000000000000101010100000000000000
[        36] 000010000000100000000000000000000000000000000000000000000000000000001000000010000000000000
[        37] 000101000001010000000000000000000000000000000000000000000000000000010100000101000000000000
[        38] 001000100010001000000000000000000000000000000000000000000000000000100010001000100000000000
[        39] 010101010101010100000000000000000000000000000000000000000000000001010101010101010000000000
#fx(536879104 0 33554944)
0
```

Ruby

{{trans|Python}}

```def notcell(c)
c.tr('01','10')
end

def eca_infinite(cells, rule)
neighbours2next = Hash[8.times.map{|i|["%03b"%i, "01"[rule[i]]]}]
c = cells
Enumerator.new do |y|
loop do
y << c
c = notcell(c[0])*2 + c + notcell(c[-1])*2        # Extend and pad the ends
c = (1..c.size-2).map{|i| neighbours2next[c[i-1..i+1]]}.join
end
end
end

if __FILE__ == \$0
lines = 25
for rule in [90, 30]
puts "\nRule: %i" % rule
for i, c in (0...lines).zip(eca_infinite('1', rule))
puts '%2i: %s%s' % [i, ' '*(lines - i), c.tr('01', '.#')]
end
end
end
```

The output is the same as the Python entry.

Sidef

{{trans|Perl}}

```func evolve(rule, bin) {
var offset = 0
var (l='', r='')
Inf.times {
bin.sub!(/^((.)\g2*)/, {|_s1, s2| l = s2; offset -= s2.len; s2*2 })
bin.sub!(/(.)\g1*\$/, {|s1| r = s1; s1*2 })
printf("%5d| %s%s\n", offset, ' ' * (40 + offset), bin.tr('01','.#'))
bin = [l*3, 0.to(bin.len-3).map{|i| bin.substr(i, 3) }..., r*3 ].map { |t|
1 & (rule >> t.bin)
}.join
}
}

evolve(90, "010")
```

{{out}}

```
-1|                                        ..#..
-2|                                       ..#.#..
-3|                                      ..#...#..
-4|                                     ..#.#.#.#..
-5|                                    ..#.......#..
-6|                                   ..#.#.....#.#..
-7|                                  ..#...#...#...#..
-8|                                 ..#.#.#.#.#.#.#.#..
-9|                                ..#...............#..
-10|                               ..#.#.............#.#..
-11|                              ..#...#...........#...#..
-12|                             ..#.#.#.#.........#.#.#.#..
-13|                            ..#.......#.......#.......#..
-14|                           ..#.#.....#.#.....#.#.....#.#..
-15|                          ..#...#...#...#...#...#...#...#..
-16|                         ..#.#.#.#.#.#.#.#.#.#.#.#.#.#.#.#..
-17|                        ..#...............................#..
-18|                       ..#.#.............................#.#..
-19|                      ..#...#...........................#...#..
-20|                     ..#.#.#.#.........................#.#.#.#..
⋮

```

Tcl

{{works with|Tcl|8.6}}

```package require Tcl 8.6

oo::class create InfiniteElementaryAutomaton {
variable rules
# Decode the rule number to get a collection of state mapping rules.
# In effect, "compiles" the rule number
constructor {ruleNumber} {
set ins {111 110 101 100 011 010 001 000}
set bits [split [string range [format %08b \$ruleNumber] end-7 end] ""]
foreach input {111 110 101 100 011 010 001 000} state \$bits {
dict set rules \$input \$state
}
}

# Apply the rule to an automaton state to get a new automaton state.
# We wrap the edges; the state space is circular.
method evolve {left state right} {
set state [list \$left {*}\$state \$right]
set len [llength \$state]
for {set i -1;set j 0;set k 1} {\$j < \$len} {incr i;incr j;incr k} {
set a [expr {\$i<0 ? \$left : [lindex \$state \$i]}]
set b [lindex \$state \$j]
set c [expr {\$k==\$len ? \$right : [lindex \$state \$k]}]
lappend result [dict get \$rules \$a\$b\$c]
}
return \$result
}

method evolveEnd {endState} {
return [dict get \$rules \$endState\$endState\$endState]
}

# Simple driver method; omit the initial state to get a centred dot
method run {steps {initialState "010"}} {
set cap [string repeat "\u2026" \$steps]
set s [split [string map ". 0 # 1" \$initialState] ""]
set left [lindex \$s 0]
set right [lindex \$s end]
set s [lrange \$s 1 end-1]
for {set i 0} {\$i < \$steps} {incr i} {
puts \$cap[string map "0 . 1 #" \$left[join \$s ""]\$right]\$cap
set s [my evolve \$left \$s \$right]
set left [my evolveEnd \$left]
set right [my evolveEnd \$right]
set cap [string range \$cap 1 end]
}
puts \$cap[string map "0 . 1 #" \$left[join \$s ""]\$right]\$cap
}
}

foreach num {90 30} {
puts "Rule \${num}:"
set rule [InfiniteElementaryAutomaton new \$num]
\$rule run 25
\$rule destroy
}
```

{{out}}

```
Rule 90:
………………………………………………………………….#.…………………………………………………………………
……………………………………………………………….#.#.………………………………………………………………
…………………………………………………………….#...#.……………………………………………………………
………………………………………………………….#.#.#.#.…………………………………………………………
……………………………………………………….#.......#.………………………………………………………
…………………………………………………….#.#.....#.#.……………………………………………………
………………………………………………….#...#...#...#.…………………………………………………
……………………………………………….#.#.#.#.#.#.#.#.………………………………………………
…………………………………………….#...............#.……………………………………………
………………………………………….#.#.............#.#.…………………………………………
……………………………………….#...#...........#...#.………………………………………
…………………………………….#.#.#.#.........#.#.#.#.……………………………………
………………………………….#.......#.......#.......#.…………………………………
……………………………….#.#.....#.#.....#.#.....#.#.………………………………
…………………………….#...#...#...#...#...#...#...#.……………………………
………………………….#.#.#.#.#.#.#.#.#.#.#.#.#.#.#.#.…………………………
……………………….#...............................#.………………………
…………………….#.#.............................#.#.……………………
………………….#...#...........................#...#.…………………
……………….#.#.#.#.........................#.#.#.#.………………
…………….#.......#.......................#.......#.……………
………….#.#.....#.#.....................#.#.....#.#.…………
……….#...#...#...#...................#...#...#...#.………
…….#.#.#.#.#.#.#.#.................#.#.#.#.#.#.#.#.……
….#...............#...............#...............#.…
.#.#.............#.#.............#.#.............#.#.
Rule 30:
………………………………………………………………….#.…………………………………………………………………
……………………………………………………………….###.………………………………………………………………
…………………………………………………………….##..#.……………………………………………………………
………………………………………………………….##.####.…………………………………………………………
……………………………………………………….##..#...#.………………………………………………………
…………………………………………………….##.####.###.……………………………………………………
………………………………………………….##..#....#..#.…………………………………………………
……………………………………………….##.####..######.………………………………………………
…………………………………………….##..#...###.....#.……………………………………………
………………………………………….##.####.##..#...###.…………………………………………
……………………………………….##..#....#.####.##..#.………………………………………
…………………………………….##.####..##.#....#.####.……………………………………
………………………………….##..#...###..##..##.#...#.…………………………………
……………………………….##.####.##..###.###..##.###.………………………………
…………………………….##..#....#.###...#..###..#..#.……………………………
………………………….##.####..##.#..#.#####..#######.…………………………
……………………….##..#...###..####.#....###......#.………………………
…………………….##.####.##..###....##..##..#....###.……………………
………………….##..#....#.###..#..##.###.####..##..#.…………………
……………….##.####..##.#..######..#...#...###.####.………………
…………….##..#...###..####.....####.###.##...#...#.……………
………….##.####.##..###...#...##....#...#.#.###.###.…………
……….##..#....#.###..#.###.##.#..###.##.#.#...#..#.………
…….##.####..##.#..###.#...#..####...#..#.##.######.……
….##..#...###..####...##.#####...#.#####.#..#.....#.…
.##.####.##..###...#.##..#....#.##.#.....#####...###.

```

zkl

{{trans|D}}

```nLines,flipCell := 25, fcn(c){ (c=="1") and "0" or "1" };
foreach rule in (T(90,30)){
println("\nRule: ", rule);
ruleBits:="%08.2B".fmt(rule);  // eg 90-->"01011010"
neighs2next:=(8).pump(Dictionary(),
'wrap(n){ T("%03.2B".fmt(n), ruleBits.reverse()[n]) });
C:="1";  // C is "1"s and "0"s, I'll auto cast to Int as needed
foreach i in (nLines){
println("%2d: %s%s".fmt(i," "*(nLines - i), C.translate("01",".#")));
C=String(flipCell(C[0])*2, C, flipCell(C[-1])*2);
C=[1..C.len()-2].pump(String,'wrap(n){ neighs2next[C[n-1,3]] });
}
}
```

{{out}}

```
Rule: 90
0:                          #
1:                         #.#
2:                        #...#
3:                       #.#.#.#
4:                      #.......#
5:                     #.#.....#.#
6:                    #...#...#...#
7:                   #.#.#.#.#.#.#.#
8:                  #...............#
9:                 #.#.............#.#
10:                #...#...........#...#
11:               #.#.#.#.........#.#.#.#
12:              #.......#.......#.......#
13:             #.#.....#.#.....#.#.....#.#
14:            #...#...#...#...#...#...#...#
15:           #.#.#.#.#.#.#.#.#.#.#.#.#.#.#.#
16:          #...............................#
17:         #.#.............................#.#
18:        #...#...........................#...#
19:       #.#.#.#.........................#.#.#.#
20:      #.......#.......................#.......#
21:     #.#.....#.#.....................#.#.....#.#
22:    #...#...#...#...................#...#...#...#
23:   #.#.#.#.#.#.#.#.................#.#.#.#.#.#.#.#
24:  #...............#...............#...............#

Rule: 30
0:                          #
1:                         ###
2:                        ##..#
3:                       ##.####
4:                      ##..#...#
5:                     ##.####.###
6:                    ##..#....#..#
7:                   ##.####..######
8:                  ##..#...###.....#
9:                 ##.####.##..#...###
10:                ##..#....#.####.##..#
11:               ##.####..##.#....#.####
12:              ##..#...###..##..##.#...#
13:             ##.####.##..###.###..##.###
14:            ##..#....#.###...#..###..#..#
15:           ##.####..##.#..#.#####..#######
16:          ##..#...###..####.#....###......#
17:         ##.####.##..###....##..##..#....###
18:        ##..#....#.###..#..##.###.####..##..#
19:       ##.####..##.#..######..#...#...###.####
20:      ##..#...###..####.....####.###.##...#...#
21:     ##.####.##..###...#...##....#...#.#.###.###
22:    ##..#....#.###..#.###.##.#..###.##.#.#...#..#
23:   ##.####..##.#..###.#...#..####...#..#.##.######
24:  ##..#...###..####...##.#####...#.#####.#..#.....#

```