float scale;

void setup()
{
  size(400, 400);
  background(62,140,82);
  stroke(209,13,69);
 
  scale = width/20;
}

void draw()

{ 
  for(int y=0; y<scale; y=y+3)  {
    colorMode(RGB, 62,140,82);
    fill(millis()%((y+1) * scale * 5) );
    rect(y*scale, 0, scale, height);
  }
}