<!DOCTYPE html>
<html>
<head>
<style>
body {
    margin: 0px;
    padding: 8px;
}
</style>
</head>
<body>
    <div style="width: 20px; height: auto;">
        <div style="margin-bottom: 20px; width: 20px; height: 20px;"></div>
    </div>
    <div style="margin-top: 10px; width: 20px; height: 20px;"></div>
    <div style="width: 1px; height: 1px; border: 0px solid transparent;"></div>
    <div style="width: 20px; height: 20px;">
        <div style="margin-bottom: 20px; width: 20px; height: 20px;"></div>
    </div>
    <div style="margin-top: 10px; width: 20px; height: 20px;"></div>
</body>
</html>