<feMerge>

<svg width="200" height="200" xmlns="http://www.w3.org/2000/svg">
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    <feOffset in="SourceGraphic" dx="60" dy="60" />
    <feGaussianBlur stdDeviation="5" result="blur2" />
    <feMerge>
      <feMergeNode in="blur2" />
      <feMergeNode in="SourceGraphic" />
    </feMerge>
  </filter>

  <rect
    x="40"
    y="40"
    width="100"
    height="100"
    stroke="black"
    fill="green"
    filter="url(#feOffset)" />
</svg>