void setup() {
  size(640, 360);
  background(255);
  noStroke();
  noLoop();
}

void draw() {
  
  drawCircles(320,  165,  300,  5, 0, 255, 0);    //prasinoi kykloi
  
  drawCircles(width/4,  height/4,  150,  8, 255, 0, 0);    // kokkinoi kykloi
    
  drawCircles(550, 50, 150, 4, 0, 0, 255);    // mple kykloi
  
  drawCircles(50, 250, 100, 6, 255, 0, 255);    // mov kykloi
  
  drawCircles(450, 250, 100, 6, 255, 255, 0);    // kitrinoi kykloi

} // telos draw

void drawCircles(float x, float y, float first_diam, float number, float r, float g, float b)
{
  int i;
  float diam;
  
  diam = first_diam;

  fill(r, g, b);
  ellipse(x, y, diam, diam);

  for (i=1; i<=number-1; i++)
  {
    diam = diam - first_diam/number;
    r = r + 255/number;
    g = g + 255/number;
    b = b + 255/number;

    fill(r, g, b);
    ellipse(x, y, diam, diam);
  }
  
} // telos drawCircles