<!DOCTYPE html>
<html>
<body>
    <div style="width: 20px; height: 20px;"></div>
    <div style="position: absolute; left: 20px; top: 0px; width: 20px; height: 20px;">
        <div style="width: 20px; height: 20px;"></div>
    </div>
</body>
</html>