<!DOCTYPE html>
<html>
<body>
<div style="float: left; width: 10px; height: 100px;"></div>
<div style="width: 100px; height: 50px;">
    <div style="float: left; width: 10px; height: 10px;"></div>
</div>
<div style="margin-left: 50px; width: 100px; height: 50px;">
    <div style="float: left; width: 10px; height: 10px;"></div>
</div>
</body>
</html>