Listing 1
<html xmlns="http://www.w3.org/1999/xhtml" lang="en" xml:lang="en">
<head>
<title>MathML's Hello Square</title>
</head>
<body>
<p> This is a perfect square:</p>
<math xmlns="http://www.w3.org/1998/Math/MathML">
<mrow>
<msup>
<mfenced>
<mrow>
<mi>a</mi>
<mo>+</mo>
<mi>b</mi>
</mrow>
</mfenced>
<mn>2</mn>
</msup>
</mrow>
</math>
</body>
</html>