<!doctype html>
<html>
  <head>
    <title>form fallback</title>
    <meta charset="utf-8"/>
  </head>
  <body>

    <!-- The left (respectively right) parenthesis only has a prefix
         (respectively postfix) form which gives its stretchiness.
         In theory, the parenthesis in the middle of the <math> element are
         considered infix operators and should not stretch. Let's check that we
         fallback to the postfix/prefix forms and actually make them stretchy.
         This is to handle bad MathML markup that misses explicit <mrow> tags.
      -->

    <math>
      <mo>(</mo> <mspace height="3em" depth="3em"/> <mo>)</mo>
      <mo>(</mo> <mspace height="3em" depth="3em"/> <mo>)</mo>
    </math>

  </body>
</html>