Shruti Nivas, a product designer in Pune, India, developed this design that she calls "Sign." It's a navigational cane for visually impaired people. It has 2 buttons, one of which has a raised mark so that the user can distinguish between them. They light up the surface either red or green.
The red light alerts passersby that the user is attempting to cross a street, board a bus, or perform some other possibly dangerous task. The green light is a request for assistance.
Assuming that people can learn what the 2 lights mean, this cane could be helpful to users trying to get around in a world designed for the sighted.