Task: Conway's Game of Life
C: #include <stdio.h>
#include <stdlib.h>
#include <unistd.h>

#define for_x for (int x = 0; x < w; x++)
#define for_y for (int y = 0; y < h; y++)
#define for_xy for_x for_y
void show(void *u, int w, int h)
{
	int (*univ)[w] = u;
	printf("\033[H");
	for_y {
		for_x printf(univ[y][x] ? "\033[07m  \033[m" : "  ");
		printf("\033[E");
	}
	fflush(stdout);
}

void evolve(void *u, int w, int h)
{
	unsigned (*univ)[w] = u;
	unsigned new[h][w];

	for_y for_x {
		int n = 0;
		for (int y1 = y - 1; y1 <= y + 1; y1++)
			for (int x1 = x - 1; x1 <= x + 1; x1++)
				if (univ[(y1 + h) % h][(x1 + w) % w])
					n++;

		if (univ[y][x]) n--;
		new[y][x] = (n == 3 || (n == 2 && univ[y][x]));
	}
	for_y for_x univ[y][x] = new[y][x];
}

void game(int w, int h)
{
	unsigned univ[h][w];
	for_xy univ[y][x] = rand() < RAND_MAX / 10 ? 1 : 0;
	while (1) {
		show(univ, w, h);
		evolve(univ, w, h);
		usleep(200000);
	}
}

int main(int c, char **v)
{
	int w = 0, h = 0;
	if (c > 1) w = atoi(v[1]);
	if (c > 2) h = atoi(v[2]);
	if (w <= 0) w = 30;
	if (h <= 0) h = 30;
	game(w, h);
}

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]]