<!DOCTYPE html>
<html>
<body>
<div style="width: 500px; height: 100px;">
    <div style="float: right; width: 50px; height: 250px;"></div>
    <div style="float: right; width: 50px; height: 250px;"></div>
    <div style="float: right; width: 50px; height: 250px;"></div>
</div>
<div style="clear: both; width: 10px; height: 100px;"></div>
<div style="float: right; width: 50px; height: 350px;"></div>
<div style="float: right; width: 50px; height: 250px;"></div>
<div style="clear: both; width: 10px; height: 100px;"></div>
<div style="float: left; width: 50px; height: 500px;"></div>
<div style="float: right; width: 50px; height: 350px;"></div>
</body>
</html>