import java.awt.*;
import java.applet.*;
public class BoxCircleAnimation extends Applet implements Runnable
{
	Thread thread;
	int delay;
	int pos=1;
	int flag=0;

	public void start()
	{
		thread = new Thread(this);
		thread.start();
		delay = 100;
	}

	public void run()
	{
		while(Thread.currentThread()==thread)
		{
			repaint();
			if(flag==0) {                                   
				pos = pos+10;                                    
			}
			else {
				pos = pos-10;
			}
			
			if(pos >= 300)
				flag = 1;
			
			if(pos <= 10)
				flag = 0;
			
			try
			{
				Thread.sleep(delay);
			}
			catch(InterruptedException e){}
		}
	}

	public void paint(Graphics g)
	{                
		g.setColor(Color.green);
		g.fillRect(100, pos, 30, 30);
		g.setColor(Color.red);
		g.fillOval(pos, 100, 30, 30);
	}

	public void stop()
	{
		thread = null;
	}
}
/*	<applet code=BoxCircleAnimation.class width=300 height=300>
 	</applet>	*/