b
  oo
 aaa
tttt

String s = "boat";

   for(int e=0; e<s.length(); e++)
   {
      for (int k=0; k<6-e; k++)
      {
         System.out.print(" ");
      }
      for (int j=0; j<e+1; j++)
      {
         System.out.print(s.charAt(e));
      }

      System.out.println("");
  }