3D printing has just recently started started to see mainstream use but the US Army is already pushing for advances in 4D printing.
The U.S. Army Research Office has awarded $855,000 to three universities to make advances in 4D printing, which is the ability to 3D-print objects that can change their shape or appearance over time (the fourth dimension), or in response to some condition. Potential uses for the technology are endless, but ideas that have been floated include camouflage that can change color to match its surroundings and weapons that can assemble themselves.
