<svg xmlns="http://www.w3.org/2000/svg">
  <linearGradient id="lg">
    <stop stop-color="rgba(128,0,0,0)" stop-opacity="0.5"/>
  </linearGradient>
  <radialGradient id="rg">
    <stop stop-color="rgba(128,0,0,0)" stop-opacity="0.5"/>
  </radialGradient>
  <rect width="100" height="100" fill="#008000"/>
  <rect width="50" height="100" fill="url(#lg)"/>
  <rect x="50" width="50" height="100" fill="url(#rg)"/>
</svg>