import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
import java.util.Random;
public class RandomWalkT extends JPanel implements ActionListener {

    //JButton b = new JButton("Walk");  *** Won't be needed ***
    int size = 400;
    int psize = 16;
    int xpos = size/2-psize/2, ypos = size/2-psize/2;
    int step = 30;
    Random random = new Random();
    int delay = 300;
    Timer timer = new Timer(delay,this); // *** create Timer, timer
                                         // *** will use this ActionListener
    public RandomWalkT () {
	setBackground(Color.white);
	//add(b);                        // *** not needed any more
	//b.addActionListener(this);     // *** don't listen to the button
	timer.start();                   // *** start Timer
    }

    public void actionPerformed(ActionEvent e) {
	xpos += random.nextInt(step)-step/2;
	ypos += random.nextInt(step)-step/2;
	repaint();
	if (delay > 10) {                // *** Change speed, speed up
	    delay -= 10;                 // *** movement, faster and faster
	    timer.setDelay(delay);       // *** until delay time is 10ms.
	}
    }

    public void paintComponent (Graphics g) {
	super.paintComponent(g);
	g.setColor(Color.magenta);
        g.fillOval(xpos, ypos, 16, 16);
    }

    public static void main(String[] u) {
	JFrame f = new JFrame();
	f.setSize(400, 400);
	f.add(new RandomWalkT());
	f.setVisible(true);
	f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    }
}