css/motion/offset-path-shape-rect-002.html

<!doctype html>
<meta charset="utf-8">
<title>CSS Motion Path test: &lt;basic-shape&gt; rect() path with explicit arguments and radius</title>
<link rel="author" title="Daniil Sakhapov" href="sakhapov@google.com">
<link rel="match" href="offset-path-shape-rect-002-ref.html">
<link rel="help" href="https://drafts.fxtf.org/motion/#valdef-offset-path-basic-shape">

<style>
#outer {
  top: 100px;
  left: 100px;
  position: relative;
  width: 600px;
  height: 400px;
}
#box {
  background-color: green;
  position: relative;
  offset-path: rect(5px 95% 95% 5px round 30%);
  offset-distance: 45%;
  offset-anchor: 10% 10%;
  width: 100px;
  height: 100px;
}
</style>

<div id="outer">
  <div id="box"></div>
</div>