, base set we move the base in the xz plane, we
move the sphere up and down using <a href="/docs/#api/en/math/Math.abs(Math.sin(time))"><code class="notranslate" translate="no">Math.abs(Math.sin(time))</code></a>
which gives us a bouncy animation. And, we also set the shadow material's
opacity so that as each sphere goes higher its shadow fades out.</p>
<pre class="prettyprint showlinemods notranslate lang-js" translate="no">function render(time) {
  time *= 0.001;  // convert to seconds

  ...

  sphereSha