Full screen flash question

I was browsing sites and came across http://www.flipvisual.com/clients/instinct-studios/

I’m curious as to how they have the images on the bottom left and right move along the borders of the browser if you resize your window. Are they different .swf’s in frames or div tags?

I understand how to full screen a flash file, just not sure how to get components in your flash movie to react according to the edge of the browser window.