<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>Conforming HTML table</title>
</head>
<body>
<table>
<tr><td colspan='2'>1</td><td>2</td></tr>
<tr><td>3</td><td colspan='2'>4</td></tr>
</table>
</body>
</html>