egaku is a tabletop user interface designed to enhance the ideation process with seamless image management tools. Designers sketch ideas as the system captures high-resolution images of the sketches and organizes them in a transparent image management structure. The system's ability to determine and recognize layer associations allows users to quickly and intuitively visualize, retrieve, navigate through, and switch between layers of information without the hassle of traversing through multiple sheets of paper.
With its strong emphasis on maintaining and enhancing the natural affordances of physical tracing paper, egaku allows users to overlay multiple digital translucent images to compose and compare different designs.
(Source: http://tangible.media.mit.edu/projects/egaku/)