<?xml version="1.0" encoding="UTF-8"?>
<svg width="800" height="600" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink">
  <rect>
    <pattern id="patternBase" width="1" height="1">
      <rect/>
    </pattern>
  </rect>

  <pattern xlink:href="#patternBase" id="pattern"/>

  <rect width="100" height="100" fill="url(#pattern)"/>

  <text x="100" y="100">PASS: did not crash.</text>
</svg>