<!DOCTYPE html>
<base href="http://www.example.com/">
<svg>
    <linearGradient id="paint">
        <stop stop-color="green"/>
    </linearGradient>
    <linearGradient id="inheritedPaint" href="#paint"/>
    <rect x="25" y="25" width="50" height="50" stroke="url(#paint) red" stroke-width="50"/>
    <rect x="125" y="25" width="50" height="50" stroke="url(#inheritedPaint) red" stroke-width="50"/>
</svg>