hoberman retractable iris dome /expanding ring system?

hello out there!

does anyone know how to make a retracting/expanding iris dome??

I'm hoping to create one as a planar surface (https://www.youtube.com/watch?v=KBNN1kRQGak&feature=related - for physical model), but any info or help on iris dome would be great! i havent a clue even where to start with this definition. if any one has any basic ideas pleeease let me know i'm becoming a rather desperate thesis student...

thanks!