<html xmlns="http://www.w3.org/1999/xhtml">
<body>
 <table>
   <tr>
      <td>x</td>
      <td rowspan="4" colspan="4">y</td>
   </tr>
   <tr>
      <td rowspan="0" colspan="0">z</td>
      <td>w</td>
   </tr>
 </table> 
</body>
</html>