Dinosaur [] jPark;
 private void btnPoly_Click(object sender, System.EventArgs e) {
   lstDino.Items.Clear();
   jPark = new Dinosaur [4];
   jPark[0] = new Lessemsaurus("lessaemsaurus", 7);
   jPark[1] = new Allosaurus("allosaurus", 12);
   jPark[2] = new TRex("tRex", 14);
   jPark[3] = new Diplodocus("doc", 9);
   Array.Sort (jPark);   // sort uses IComparable   
   foreach (Dinosaur dino in jPark){
      lstDino.Items.Add(dino.Name);
   }
 }