import java.awt.Frame;
import java.awt.Color;

BouncingWindow w[];

void setup()
{
  w = new BouncingWindow[8];
  for (int i = 0; i < w.length; i++)
    w[i] = new BouncingWindow();
}

void draw()
{
  frame.setVisible(false);
  for (int i = 0; i < w.length; i++)
    w[i].draw();
}


class BouncingWindow
{
  Frame frame;
  
  final static int SIZE = 20;
  float x, y;
  float vx, vy;
  
  BouncingWindow()
  {
    x = random(0, screen.width - SIZE);
    y = random(0, screen.height - SIZE);
    vx = random(-20, 20);
    vy = random(-20, 20);

    frame = new Frame();
    frame.setSize(SIZE, SIZE);
    frame.setLocation(floor(x), floor(y));
    frame.setUndecorated(true);
    frame.setAlwaysOnTop(true);
    frame.setBackground(new Color(random(1), random(1), 1));
    frame.setVisible(true);
  }
  
  void draw()
  {
    x += vx;
    y += vy;

    if (x < 0) { x = 0; vx *= -1; }
    if (x > screen.width - SIZE) { x = screen.width - SIZE; vx *= -1; }
    if (y < 0) { y = 0; vy *= -1; }
    if (y > screen.height - SIZE) { y = screen.height - SIZE; vy *= -1; }

    frame.setLocation(floor(x), floor(y));
  }
}