<!DOCTYPE html>
<head>
<base href="/test">
</head>
<body style="background-color: lime;">
  <svg width="100" height="100">
    <defs>
      <rect id="a" x="0" y="0" width="50" height="50" fill="lime"/>
    </defs>
    <rect x="0" y="0" width="50" height="50" fill="red"/>
    <use xlink:href="#a"/>
  </svg>
</body>
</html>