import java.awt.*; public class Ball extends java.applet.Applet implements Runnable { Thread runner; int x,y; public void start() { if( runner==null ) { runner=new Thread(this); runner.start(); } } public void stop() { if( runner!=null ) { runner.stop(); runner=null; } } public void run() { int i=0; for(x=0; x<=255; x++) { y=x; repaint(); try { Thread.sleep(100); } catch( InterruptedException e ) { } } } public void paint(Graphics g) { g.fillOval(x,y,20,20); } }