cx

html,
body,
svg {
  height: 100%;
}

<svg viewBox="0 0 300 100" xmlns="http://www.w3.org/2000/svg">
  <radialGradient cx="25%" id="myGradient">
    <stop offset="0" stop-color="white" />
    <stop offset="100%" stop-color="black" />
  </radialGradient>

  <circle cx="50" cy="50" r="45" />
  <ellipse cx="150" cy="50" rx="45" ry="25" />
  <rect x="205" y="5" width="90" height="90" fill="url(#myGradient)" />
</svg>

html,
body,
svg {
  height: 100%;
}

<svg viewBox="0 0 34 10" xmlns="http://www.w3.org/2000/svg">
  <defs>
    <radialGradient cx="0" id="myGradient000">
      <stop offset="0%" stop-color="gold" />
      <stop offset="50%" stop-color="green" />
      <stop offset="100%" stop-color="white" />
    </radialGradient>

    <radialGradient cx="50%" id="myGradient050">
      <stop offset="0%" stop-color="gold" />
      <stop offset="50%" stop-color="green" />
      <stop offset="100%" stop-color="white" />
    </radialGradient>

    <radialGradient cx="100%" id="myGradient100">
      <stop offset="0%" stop-color="gold" />
      <stop offset="50%" stop-color="green" />
      <stop offset="100%" stop-color="white" />
    </radialGradient>
  </defs>

  <rect
    x="1"
    y="1"
    width="8"
    height="8"
    fill="url(#myGradient000)"
    stroke="black" />
  <rect
    x="13"
    y="1"
    width="8"
    height="8"
    fill="url(#myGradient050)"
    stroke="black" />
  <rect
    x="25"
    y="1"
    width="8"
    height="8"
    fill="url(#myGradient100)"
    stroke="black" />
</svg>