<!DOCTYPE html>
<html>
<body>
    <div style="width: 20px; height: auto;">
        <div style="margin-bottom: 1px; width: 20px; height: 20px;">
            <div style="margin-bottom: 5px; width: 20px; height: 20px;">
                <div style="margin-bottom: 10px; width: 20px; height: 20px;">
                    <div style="margin-bottom: 20px; width: 20px; height: 20px;"></div>
                </div>
            </div>
        </div>
    </div>
    <div style="margin-top: 10px; width: 20px; height: 20px;"></div>
</body>
</html>