Campaign, who are taking part in this year's London Design Festival, created this beautiful pop-up cardboard Foldaway Bookshop (above) for the London Festival of Architecture. The nice thing about cardboard is that it's the ultimate recyclable.

How far can you stretch that thought, though? Take a look at this carboard furniture that was exhibited Melbourne's recent State of Design Festival. Flatform 322 is a fold-down cardboard set designed and build by Toby Horrocks and Christine Aus. Horrocks and Aus ask, "Do you design for longevity and hope your designs don't prematurely end up in the skip? Or go with the flow and accept that change is inevitable?" They have created an interior space that is made of 100% recyclables and which is itself entirely recyclable. 

Foldaway Shop photo by Paul Greanleaf via b3designers blog.
Flatform 322 via Core77 Magazine