// Add key listener.
		this.addKeyListener
		(
			new KeyAdapter() {
				public void keyPressed(KeyEvent e) {
					int k = e.getKeyCode();
					if (k==37) x = x - 10;
					if (k==38) y = y - 10;
					if (k==39) x = x + 10;
					if (k==40) y = y + 10;
					repaint();
				}
			}
		);
      }