<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" height="200" width="200">
<title>The rectangle should be split; white on the top, green on the bottom.</title>
<defs>
  <linearGradient id="gradient" x2="0%" y2="100%">
    <stop offset="0" stop-color="white"/>
    <stop offset="0.5" stop-color="white"/>
    <stop offset="0.5" stop-color="green"/>
    <stop offset="1" stop-color="green"/>
  </linearGradient>
  <pattern id="shot" patternUnits="userSpaceOnUse" width="400" height="400">
    <rect height="400" width="400" fill="url(#gradient)"/>
  </pattern>
</defs>
<rect transform="translate(0,-100)" x="0" y="100" width="200" height="200" fill="url(#shot)" stroke="black"/>
</svg>