div style="position: absolute; top: 300px; width: 200px; height: 200px">
    <math style="position: absolute; clip-path: polygon(10% 10%, 90% 10%, 90% 90%, 10% 90%)"><mspace width="200px" height="200px" style="background: green"/></math>
  </div>
  <script src="/mathml/support/feature-detection.js"></script>
  <script>MathMLFeatureDetection.ensure_for_match_reftest("has_mspace");</script>
</body>
</html>
