Task: Conway's Game of Life
C++: #include <algorithm>
#include <vector>
#include <iostream>
#include <string>

typedef unsigned char byte; 

class world {
public:
    world( int x, int y ) : _wid( x ), _hei( y ) {
        int s = _wid * _hei * sizeof( byte );
        _cells = new byte[s];
        memset( _cells, 0, s );
    }
    ~world() {
        delete [] _cells;
    }
    int wid() const {
        return _wid;
    }
    int hei() const {
        return _hei;
    }
    byte at( int x, int y ) const {
        return _cells[x + y * _wid];
    }
    void set( int x, int y, byte c ) {
        _cells[x + y * _wid] = c;
    }
    void swap( world* w ) {
        memcpy( _cells, w->_cells, _wid * _hei * sizeof( byte ) );
    }
private:
    int _wid, _hei;
    byte* _cells;
};
class rule {
public:
    rule( world* w ) : wrd( w ) {
        wid = wrd->wid();
        hei = wrd->hei();
        wrdT = new world( wid, hei );
    }
    ~rule() {
        if( wrdT ) delete wrdT;
    }
    bool hasLivingCells() {
        for( int y = 0; y < hei; y++ )
            for( int x = 0; x < wid; x++ )
                if( wrd->at( x, y ) ) return true;
        std::cout << "*** All cells are dead!!! ***\n\n";
        return false;
    }
    void swapWrds() {
        wrd->swap( wrdT );
    }
    void setRuleB( std::vector<int>& birth ) {
        _birth = birth;
    }
    void setRuleS( std::vector<int>& stay ) {
        _stay = stay;
    }
    void applyRules() {
        int n;
        for( int y = 0; y < hei; y++ ) {
            for( int x = 0; x < wid; x++ ) {
                n = neighbours( x, y );
                if( wrd->at( x, y ) ) {
                    wrdT->set( x, y, inStay( n ) ? 1 : 0 );
                } else {
                    wrdT->set( x, y, inBirth( n ) ? 1 : 0 );
                }
            }
        }
    }
private:
    int neighbours( int xx, int yy ) {
        int n = 0, nx, ny;
        for( int y = -1; y < 2; y++ ) {
            for( int x = -1; x < 2; x++ ) {
                if( !x && !y ) continue;
                nx = ( wid + xx + x ) % wid;
                ny = ( hei + yy + y ) % hei;
                n += wrd->at( nx, ny ) > 0 ? 1 : 0;
            }
        }
        return n;
    }
    bool inStay( int n ) {
        return( _stay.end() != find( _stay.begin(), _stay.end(), n ) );
    }
    bool inBirth( int n ) {
        return( _birth.end() != find( _birth.begin(), _birth.end(), n ) );
    }
    int wid, hei;
    world *wrd, *wrdT;
    std::vector<int> _stay, _birth;
};
class cellular {
public:
    cellular( int w, int h ) : rl( 0 ) {
        wrd = new world( w, h );
    }
    ~cellular() {
        if( rl ) delete rl;
        delete wrd;
    }
    void start( int r ) {
        rl = new rule( wrd );
        gen = 1;
        std::vector<int> t;
        switch( r ) {
            case 1: 
                t.push_back( 2 ); t.push_back( 3 ); rl->setRuleS( t );
                t.clear(); t.push_back( 3 ); rl->setRuleB( t );
                break;
            case 2: 
                t.push_back( 1 ); t.push_back( 3 ); t.push_back( 5 ); t.push_back( 8 ); rl->setRuleS( t );
                t.clear(); t.push_back( 3 ); t.push_back( 5 ); t.push_back( 7 ); rl->setRuleB( t );
                break;
            case 3: 
                t.push_back( 3 ); t.push_back( 4 ); rl->setRuleS( t );
                rl->setRuleB( t );
                break;
            case 4: 
                t.push_back( 1 ); t.push_back( 2 ); t.push_back( 3 ); t.push_back( 4 ); t.push_back( 5 ); rl->setRuleS( t );
                t.clear(); t.push_back( 3 ); rl->setRuleB( t );
                break;
        }

        
        
        wrd->set( 6, 1, 1 ); wrd->set( 7, 2, 1 );
        wrd->set( 5, 3, 1 ); wrd->set( 6, 3, 1 );
        wrd->set( 7, 3, 1 );
        
        wrd->set( 1, 3, 1 ); wrd->set( 2, 3, 1 );
        wrd->set( 3, 3, 1 );
        
        generation();
    }
private:
    void display() {
        system( "cls" );
        int wid = wrd->wid(),
            hei = wrd->hei();
        std::cout << "+" << std::string( wid, '-' ) << "+\n";
        for( int y = 0; y < hei; y++ ) {
            std::cout << "|";
            for( int x = 0; x < wid; x++ ) {
                if( wrd->at( x, y ) ) std::cout << "#";
                else std::cout << ".";
            }
            std::cout << "|\n";
        }
        std::cout << "+" << std::string( wid, '-' ) << "+\n";
        std::cout << "Generation: " << gen << "\n\nPress [RETURN] for the next generation...";
        std::cin.get();
    }
    void generation() {
        do {
            display();
            rl->applyRules();
            rl->swapWrds();
            gen++;
        }
        while ( rl->hasLivingCells() );
    }
    rule* rl;
    world* wrd;
    int gen; 
};

int main( int argc, char* argv[] ) {
    cellular c( 20, 12 );
    std::cout << "\n\t*** CELLULAR AUTOMATA ***" << "\n\n Which one you want to run?\n\n\n";
    std::cout << " [1]\tConway's Life\n [2]\tAmoeba\n [3]\tLife 34\n [4]\tMaze\n\n > ";
    int o; 
    do {
        std::cin >> o;
    } 
    while( o < 1 || o > 4 );
    std::cin.ignore();
    c.start( o );
    return system( "pause" );
}

Python: cell_size = 10
sample = 10 
play = False   
last_cell = 0

def setup():
    global grid, next_grid, rows, cols
    size(800, 500)

    rows = height / cell_size
    cols = width / cell_size
    grid = empty_grid()
    next_grid = empty_grid()
    randomize_grid()

    println("Press 'space' to start/stop")
    println("'e' to clear all cells")
    println("'b' demonstrate 'blinker'")
    println("'g' demonstrate glider")
    println("'r' to randomize grid")
    println("'+' and '-' to change speed")

def draw():
    background(0)
    for i in range(cols):
        x = i * cell_size
        for j in range(rows):
            y = j * cell_size
            current_state = grid[i][j]
            fill(255)
            noStroke()
            if current_state:
                rect(x, y, cell_size, cell_size)
            if play:
                ngbs_alive = calc_ngbs_alive(i, j)
                result = rule(current_state, ngbs_alive)
                next_grid[i][j] = result
                
    if play and frameCount % sample == 0 and not mousePressed:
        step()

def rule(current, ngbs):
    
    if ngbs < 2 or ngbs > 3:
        return 0  
    elif ngbs == 3:
        return 1  
    else:
        return current  

def calc_ngbs_alive(i, j):
    NEIGHBOURS = ((-1, 00), (01, 00),  
                  (-1, -1), (00, -1),
                  (01, -1), (-1, 01),
                  (00, 01), (01, 01))
    alive = 0
    for iv, jv in NEIGHBOURS:
        alive += grid[(i + iv) % cols][(j + jv) % rows]
    return alive

def empty_grid():
    grid = []
    for _ in range(cols):
        grid.append([0] * rows)
    return grid

def randomize_grid():
    from random import choice
    for i in range(cols):
        for j in range(rows):
            grid[i][j] = choice((0, 1))

def step():
    global grid, next_grid
    grid = next_grid
    next_grid = empty_grid()

def keyReleased():
    global grid, play, sample
    if key == "e":
        grid = empty_grid()
    if key == "r":
        randomize_grid()
    if key == "g":
         grid[10][10:13] = [0, 1, 0]       
         grid[11][10:13] = [0, 0, 1]       
         grid[12][10:13] = [1, 1, 1]       
    if key == "b":
         grid[10][10:13] = [0, 1, 0]       
         grid[11][10:13] = [0, 1, 0]       
         grid[12][10:13] = [0, 1, 0]               
    if key == " ":
        play = not play 
    if  str(key) in '+=':
        sample = max(sample - 1, 1);
    if key == '-':
        sample += 1

def mousePressed():
    paint()
    
def mouseDragged():
    paint()

def paint():
    global last_cell
    i, j = mouseX // cell_size, mouseY // cell_size
    p = j * cols + i
    if p != last_cell:
        last_cell = p
        grid[i][j] = (1, 0)[grid[i][j]]