Life

function simulate()
    local m = #cell
    local cell2 = {}
    for i = 1, m do
        cell2[i] = {}
        for j = 1, m do
            cell2[i][j] = cell[i][j]
        end
    end

    for i = 1, m do
        for j = 1, m do
            local count
            if cell2[i][j] == 0 then count = 0 else count = -1 end
            for x = -1, 1 do
                for y = -1, 1 do
                    if i+x >= 1 and i+x <= m and j+y >= 1 and j+y <= m and cell2[i+x][j+y] == 1 then count = count + 1 end
                end
            end
            if count < 2 or count > 3 then cell[i][j] = 0 end
            if count == 3 then cell[i][j] = 1 end
        end
    end
 end

function init()
    speed=0.25
    local null,x=term.getSize()
    print("Recommended size is "..x-1)
    write("Size:")
    size=tonumber(read())
    cell={}
    for i=1,size do
        cell[i]={}
        for ia=1,size do
            cell[i][ia]=math.random(0,1)
        end
    end
end

function draw()
    term.clear()
    term.setCursorPos(1,1)
    for k,v in ipairs(cell) do
        for key,cs in ipairs(v) do
            if cs==0 then
                write(" ")
            else
                write("#")
            end
        end
        print("")
    end
    if not sim then
      write("Paused")
    else
      write("Speed:"..speed)
    end
    term.setCursorPos(xsel,ysel)
    if cell[ysel][xsel]==0 then
      write("+")
    else
      write("@")
    end
end

init()
sim=true
xsel=1
ysel=1
while true do
    if sim then
        simulate()
    end
    os.startTimer(speed)
    e,k=os.pullEvent()
    if e=="key" or e=="char" then
        	os.pullEvent("timer")
        if k==keys["up"] then
            if ysel~=1 then
                ysel=ysel-1
            end
        elseif k==keys["down"] then
            if ysel~=size then
                ysel=ysel+1
            end
        elseif k==keys["left"] then
            if xsel~=1 then
                xsel=xsel-1
            end
        elseif k==keys["right"] then
            if xsel~=size then
                xsel = xsel + 1
            end
        elseif k==keys["enter"] then
            if cell[ysel][xsel]==0 then
                cell[ysel][xsel]=1
            else
                cell[ysel][xsel]=0
            end
        elseif k==keys["p"] then
            sim=not sim
        elseif k==13 then
          speed=speed+0.05
        elseif k==12 then
          if speed>0 then
            speed=speed-0.05
          end
        end
    end
    draw()
end