From video description:
This folding stool, called "One__Shot.MGX", was manufactured using a 3D printing process known as selective laser sintering. It is made from Polyamide, a type of nylon plastic. The stool was designed by Patrick Jouin in 2006 and acquired into the Cooper Hewitt Museum's collection in 2008.There are many interesting furniture pieces produced by additive manufacturing and digital fabrication methods, see some examples here:
http://diy3dprinting.blogspot.com/search/label/furniture
Source:
http://collection.cooperhewitt.org/objects/18705701/
https://www.youtube.com/user/cooperhewitt?feature=watch