SVG Smil AnimateTransform 2

<!doctype html>
<title>Example</title>
<svg width="400" height="200" viewBox="0 0 200 100">
  
  <g transform="translate(50,50)">
    <circle cx="0" cy="0" r="10" fill="skyblue" opacity="0.5">
      <animateTransform 
        attributeName="transform" 
        type="scale" 
        from="1" 
        to="2" 
        dur="1s" 
        repeatCount="indefinite" 
        additive="sum" />
    </circle>
  </g>

<g transform="translate(150,50)">
    <circle cx="0" cy="0" r="10" fill="tomato" opacity="0.5">
      <animateTransform 
        attributeName="transform" 
        type="scale" 
        values="1;1.8;1" 
        keyTimes="0;0.5;1"
        calcMode="spline"
        keySplines="0.4 0 0.2 1; 0.4 0 0.2 1"
        dur="2s" 
        repeatCount="indefinite" 
        additive="sum" />
    </circle>
  </g>

<text x="50" y="90" font-size="6" text-anchor="middle" font-family="sans-serif">Basic Scale (Linear)</text>
  <text x="150" y="90" font-size="6" text-anchor="middle" font-family="sans-serif">Organic Pulse (Spline)</text>
</svg>