$layout = $this->getLayout();
      $sample1 = $layout->createBlock('moduletesttemplatesintro/sample1')->toHtml();
      $sample2 = $layout->createBlock('moduletesttemplatesintro/sample2')->toHtml();
      $sample3 = $layout->createBlock('moduletesttemplatesintro/sample3')->toHtml();
      $html = $sample1 . $sample2 . $sample3;

      $this->getResponse()->appendBody($html);