<divclass="container_12"><divclass="grid_4">
I am 1/3 wide.
</div><divclass="grid_4">
I am 1/3 wide.
</div><divclass="grid_4">
Mee too!
</div><divclass="clear"><divclass="grid_6">
I am 1/2 wide.
</div><divclass="grid_6">
I am 1/2 wide.
</div></div>
Nested
class="alpha" => first div without margin
class="omega" => last div without margin
Rearrangement
class="push_6" => last visually(used for changing the order that appear in the HTML)
class="pull_6" => first visually(used for changing the order that appear in the HTML)
Empty space
class="prefix_2" => insert 2 empty columns before
class="suffix_2" => insert 2 empty columns after