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<!DOCTYPE html>
<html>
<head>
<style> 
#myDIV {
  width: 300px;
  height: 200px;
  border: 1px solid black;
  animation: mymove 5s infinite;
}
@keyframes mymove {
  50% {border-radius: 50px;}
}
</style>
</head>
<body>
<h1>Animation of border-radius</h1>
<p>Gradually change the border-radius property from 0 to 50px, then back:<p>
<div id="myDIV"></div>
</body>
</html>