In this exercise, you will create a new Thread subclass that can be used in conjunction with a Java class called Morse:
class Morse {
   public static void main(String[] args) {
      DotDash d1, d2, d3;
      d1 = new DotDash('.');
      d2 = new DotDash('-');
      d3 = new DotDash(' ');
      d1.start();
      d2.start();
      d3.start();
   }
}