<svg xmlns="http://www.w3.org/2000/svg">
<clipPath id="clip2">
  <rect x="50" y="50" width="150" height="150"/>
</clipPath>
<clipPath id="clip1" clipPathUnits="objectBoundingBox" clip-path="url(#clip2)">
  <rect width="0.75" height="0.75"/>
</clipPath>
<rect height="200" width="200" fill="green" clip-path="url(#clip1)"/>
</svg>