<!DOCTYPE html>
<html>
<head>
<style>
.box {
width: 50px;
height: 50px;
background-color: red;
position: relative;
animation: move 2s infinite;
}
@keyframes move {
0% { top: 0; left: 0; }
50% { top: 200px; left: 200px; }
100% { top: 0; left: 0; }
}
</style>
</head>
<body>
<div class="box"></div>
</body>
</html>