./
./testscript.php
./templates/design01/main.tpl.htm
./templates/design01/table.tpl.htm
./templates/design02/main.tpl.htm
./templates/design02/table.tpl.htm

<?php 
  /* 
   * testscipt.php - sets a random design
   */

  require_once "HTML/Template/IT.php";

  $tpl = new HTML_Template_IT();
 
  $randomNumber = (int) round(rand(0,1));
  switch ($randomNumber) 
  {
     case 0:
         // Set root to design01 so the called main.tpl.htm is searched there
         $tpl->setRoot("./templates/design01");
         break;
     case 1:
     default:
         // Set root to design02 so the called main.tpl.htm is searched there
         $tpl->setRoot("./templates/design02");
         break;
  }

  /* Loads either ./templates/design01/main.tpl.htm
   * or ./templates/design02/main.tpl.htm depending on the root directory set
   * with setRoot in the switch */
  $tpl->loadTemplatefile("main.tpl.htm", true, true);

  /* ... assign variables .. */

  // show
  $tpl->show();

?>