I’m here to share a bit of my code, spent the last hour or so writing it and here it is, it’s Conway's Game of Life, I’ve decided to give this away since it’s quite simple and great for learning about Codea. It’s by no means perfect but it looks quite nice and it’s very simple 
Here’s the code
###Main.lua
-- golly
-- Use this function to perform your initial setup
function setup()
parameter.color("DeadCellColour", color(123,123,223,255))
parameter.color("AliveCellColour", color(10,10,10,255))
parameter.color("Background", color(255,255,255,255))
parameter.boolean("Play")
gol = Gol(15, 30)
gol.drawMethod = function (cell)
wid = WIDTH / 15
hei = HEIGHT / 30
if cell.s == gol._alive then
fill(AliveCellColour)
else
fill(DeadCellColour)
end
rect(wid * (cell.x - 1), hei * cell.y, wid, hei)
end
end
-- This function gets called once every frame
function draw()
-- This sets a dark background color
background(Background)
-- If we've paused, stop calculating
if Play then
gol:calculate()
end
-- Always draw
gol:draw()
end
function touched(t)
gol:touched(t)
end
###Gol.lua
Gol = class()
function Gol:init(W, H)
-- Set the size
self.columns = W
self.rows = H
-- The varying states of cells
self._alive = 1
self._dead = 0
-- The game states
self._paused = 0
self._stepping = 1
-- Some public things
self.matrix = {}
-- This is a method to set for a draw method
-- Called for every cell every frame
self.drawMethod = function(cell) end
-- Create a blank board
self:create()
end
function Gol:create()
for r = 1, self.rows do
table.insert(self.matrix, {})
for c = 1, self.columns do
table.insert(self.matrix[r], {})
self.matrix[r][c] = self._dead
end
end
end
function Gol:clear()
for r = 1, self.rows do
for c = 1, self.columns do
self.matrix[r][c] = self._dead
end
end
end
function Gol:alive(c, r)
if self.matrix[r][c] == self._alive then
return true
end
return false
end
function Gol:dead(c, r)
if self.matrix[r][c] == self._dead then
return true
end
return false
end
function Gol:calculate()
local n = 0
local tab = self.matrix
-- Neighbour positions from the current index
local nbrs = {
{-1,-1},
{-1,0},
{-1,1},
{0,-1},
{0,1},
{1,-1},
{1,0},
{1,1}
}
for r = 2, self.rows - 1 do
for c = 2, self.columns - 1 do
n = 0
-- How many neighbours does this cell have?
for _,a in ipairs(nbrs) do
if self:alive(c + a[2], r + a[1]) then
n = n + 1
end
end
-- Kill or live
if self:alive(c, r) and n < 2 then
tab[r][c] = self._dead
elseif self:alive(c, r) and (n == 2 or n == 3) then
tab[r][c] = self._alive
elseif self:alive(c, r) and n >= 3 then
tab[r][c] = self._dead
elseif self:dead(c, r) and n == 3 then
tab[r][c] = self._alive
end
end
end
end
function Gol:draw()
for r = 1, self.rows do
for c = 1, self.columns do
self.drawMethod({
x = c,
y = r,
s = self.matrix[r][c]
})
end
end
end
function Gol:touched(touch)
local x = math.floor(touch.x / (WIDTH / self.columns))
local y = math.floor(touch.y / (HEIGHT / self.rows))
self.matrix[y][x] = self._alive
end
Any criticism is welcome as well as improvements and ideas
###Enjoy!