Inspired by the color-changing skin of cuttlefish, octopuses and squids, Rutgers engineers have created a 3D-printed smart gel that changes shape when exposed to light, becomes “artificial muscle” and may lead to new military camouflage, soft robotics and flexible displays. The engineers also developed a 3D-printed stretchy material that can reveal colors when light changes, according to their study in the journal ACS Applied Materials & Interfaces.