Rearrange Tiles Within An Area

I'm trying to create a tile grid that can be rearranged. The tiles are of different sizes. Here's how far I've gotten. http://jsfiddle.net/psivadasan/dMtRs/ How do I prevent tiles

Solution 1:

Just use the containment option: This will stop the elements being dragged outside.

$('ul').sortable( "option", "containment", 'parent' );

http://jsfiddle.net/dazefs/dMtRs/7/