chromium/third_party/blink/web_tests/svg/custom/multiple-resource-cycles.html

<!DOCTYPE html>
<svg>
  <defs>
    <pattern id="a" width="10" height="10" patternUnits="userSpaceOnUse">
      <rect width="10" height="10" fill="url(#a) blue"/>
    </pattern>
    <pattern id="b" width="10" height="10" patternUnits="userSpaceOnUse">
      <rect width="10" height="10" fill="url(#b) lightblue"/>
    </pattern>
  </defs>
  <rect width="80" height="80" x="10" y="10"
        stroke="url(#a) green" fill="url(#b) green" stroke-width="20"/>
</svg>