Codea/codify side effect snow

--snowflakes
function setup()
    --put anywhere in setup
    flakes = {}
    for i = 1, 20 do
        flakes[i] = {cx=math.random(WIDTH),
                    cy=math.random(HEIGHT),
                    l=math.random(3,30),
                    r=math.random(60),
                    w=math.random(20)+3}
    end
end

function draw()
    --this section for demo only
    sprite("SpaceCute:Background",WIDTH/2,HEIGHT/2)
    sprite("Small World:Church",100,100)
    sprite("Small World:Court",200,300)
    sprite("Small World:Explosion",300,500)
    sprite("Small World:Tower",400,150)
    --place at end of draw loop
    stroke(255, 255, 255, 26)
    for k, v in pairs(flakes) do
        strokeWidth(flakes[k].w)
        draw_flake(flakes[k])
        flakes[k].cy = flakes[k].cy - math.random()
        --borrowed from bit invader
        sideMove = vec2( math.sin(flakes[k].cy * 0.02), 0 )
        flakes[k].cx = flakes[k].cx + sideMove.x
        flakes[k].r = flakes[k].r + math.random()
        if (flakes[k].cy + flakes[k].l) < 0 then
            flakes[k].l = math.random(3,30)
            flakes[k].cy = HEIGHT + flakes[k].l
            flakes[k].cx = math.random(WIDTH)
        end
    end
end

--required
function draw_flake(fl)
    local f = vec2(0,fl.l)
    f = f:rotate(math.rad(fl.r))
    for i = 1, 6 do
        line(fl.cx,fl.cy,fl.cx+f.x,fl.cy+f.y)
        f = f:rotate(math.rad(60))
    end
end

--alternatives: convert this to a class, isolate with pushStyle and pushMatrix