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

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

  </body>
</html>