This is just amazing. If you have not heard about the Stone Spray Project, then check them out: http://www.stonespray.com/

What this group of researchers have done is uses a special bonding agent along with natural sand, and a custom 3D printing device that sprays the sand on top of itself to create strong structures. The robot that does the printing requires very little energy and and run entirely on solar power, and the bonding agent is eco-friendly, made from LEED Certified components. The project was founded by architects Petr Novikov, Inder Shergill and Anna Kulik.





They are also ale to make a variety of other cool pieces. The sand stool: