Plastic

The University of Stuttgart’s Institute for Computational Design is experimenting with random piles of plastic and architecture. Instead of planning out the exact building and structure requirements, the institute is researching with injection molded plastic to see if small heaps of plastic pieces can be used to hold a structure instead of any support system.

From wired.com: "Instead of welding the steel frame of a building or pouring concrete into a mold, a robot could simply dump small plastic particles into a pile, causing them to form a self-stabilizing structure on their own."

On top of that the structures are interesting to look at, and are in themselves a work of art.