<div class="sidebar">

<div class="sidebar-big">
<?php dynamic_sidebar('big1'); ?>
</div>

<div class="sidebar-2column1">
<?php dynamic_sidebar('small-left1'); ?>
</div>

<div class="sidebar-2column2">
<?php dynamic_sidebar('small-right1'); ?>
</div>

<div class="sidebar-big">
<?php dynamic_sidebar('big2'); ?>
</div>

<div class="sidebar-2column1">
<?php dynamic_sidebar('small-left2'); ?>
</div>

<div class="sidebar-2column2">
<?php dynamic_sidebar('small-right2'); ?>
</div>

</div>