void setup()
{
  size(200,200);
  smooth();
}

void draw()
{
  background(255);
  stroke(0);
  noFill();
  drawCircle(width/2,height/2,100);
}

// recursive function
void drawCircle(int x, int y, int radius)
{
  // base case (do not draw any more circles after you go under
  // radius of 2)
  if (radius <= 2)
  {
    ellipse(x,y,radius,radius);
  }
  // if radius is > 2, draw a a circl, than draw  a circle with 3/4th radius of own
  else
  {
    ellipse(x,y,radius,radius);
    radius = (radius * 3)/4;
    drawCircle(x,y,radius);
  }
}