void
setup()
{
  size(200, 200);
  background(0xff);
  fill(0xff);
  noStroke();
}

void
loop()
{
  background(0xff, 0, 0);
  
  for (int y = 1; y < 9; y++) {
    for (int x = 1; x < 9; x++) {
      float dx, dy, r;
      dx = mouseX - (x * 20);
      dy = mouseY - (y * 20);
      r = sqrt(dx * dx + dy * dy) * 0.5;
      if (r < 5.0) r = 5.0;
      
      ellipse(x * 20 + (20 - r) / 2, y * 20 + (20 - r) / 2,
              r, r);
    }
   }
}