The inventor of an "invisibility" cloak says his next project will be to help people see through walls. Susumu Tachi, who showed off his cloak at an exhibition in San Francisco earlier this month, now hopes to provide a view of the outside in windowless rooms. "This technology can be used in all kinds of ways, but I wanted to create a vision of invisibility," he told BBC World Service's Outlook programme. "My short-term goal would be, for example, to make a room that has no outside windows appear to have a view to the outside, then the wall would appear to be invisible." Professor Tachi's cloak works by projecting an image onto itself of what is behind the wearer. A computer generates the image that is projected, so the viewer effectively sees "through" the cloak. There are many potential uses of the cloak, ranging from espionage and military purposes to helping pilots see through the floor of the cockpit to the runway below. However there are massive questions of potential misuse too, particularly surrounding the huge crime implications.