x = []
y = []
speed = []

def setup():
    size(800,800)
    i = 0
    while i < 10:
        x.append( random(100,width-100) )
        y.append( random(-400,0) )
        speed.append( random(1,5) )
        i = i + 1

def draw():
    background(255)
    i = 0
    while i < 10:
        fill(150)
        ellipse( x[i],y[i],10,10 )
        y[i] = y[i] + speed[i]
        if y[i] > height:
            x[i] = random(100,width-100)
            y[i] = random(-400,0)
            speed[i] = random(1,5)
        i = i + 1