public class ButtonMain {
  public static void main(String[] args) {
    // Part 1
    Button b1 = new Button( );
    Button b2 = new Button( );
    b1.tellState( );
    b2.tellState( );
    // Part 2
    b1.pushButton( );
    b1.tellState( );
    b1.clearButton( );
    b1.tellState( );
    // Part 3
    boolean buttonState = b2.getState();
    System.out.println("State of b2 is " + buttonState);
    // Part 4
    b2.pushButton();
    System.out.println(b2);
  }
}