Imagine a bottle of hazardous chemicals that changes its appearance to alert scientists if its lid is not properly secured. MIT researchers have developed a new 3D-printing system that enables users to produce interactive objects like this chemical bottle, which change their appearance when pressed, slid, or turned, without the use of any internal electronics. The system combines specially arranged optical layers with built-in mechanical parts, allowing a single object to display different images or patterns. The resulting objects change appearance based on user interactions like screwing on a lid or flipping a switch, and they can be manufactured in one pass on a multimaterial 3D printer. The researchers developed a user-friendly tool called ShiftLens, which automatically generates a ShiftLens structure based on a few inputs, including images of the visual states the user wants to achieve and the desired shape and curves of the object. The researchers showcased the potential of ShiftLens by fabricating a range of interactive objects, including a chemical bottle that turns green and displays a check mark when the cap is securely tightened, and a tic-tac-toe game with squares that can display a red X, a blue O, or no letter, depending on which direction a user turns a knob. Blogger's Review: This technology has the potential to revolutionize the way we interact with objects, providing a more intuitive and intelligent user experience. In the future, the researchers plan to further develop ShiftLens, simplifying the design process and expanding its applications.