Called PhotoCromeleon, the project involved mixing photochromic cyan, magenta and yellow dyes to create an ink. In its original state, this ink is transparent; however, the photosensitive dyes react to certain wavelengths of UV light and change their color. This color remains until exposed to a UV wavelength that returns it to its translucent state.
The MIT team programmed UV projectors to project patterns onto real-life objects based on 3-D computer models of them. They were able to change the designs on a phone case, a toy car and, fittingly, a 3-D-printed toy chameleon.