import java.applet.*;
import java.awt.*;

// Extend this applet to write a simple animation.

public abstract class BasicAnimationApplet extends DoubleBufferApplet
                                           implements Runnable {

  Thread t;
  int sleepMillis = 40;

  public void start() {
    t = new Thread(this);
    t.start();
  }

  public void stop() { t =  null; }

  public void run() {
    while (Thread.currentThread() == t) {
      step();
      repaint();
      try { Thread.sleep(sleepMillis); }
      catch (InterruptedException e) { return; }
    }
  }

  abstract void step();
  public abstract void paint(Graphics g);
}