A huge electronic display on a skyscraper facade can be interesting to passing pedestrians, but if you're inside the building it simply blocks your view. Researchers at MIT's Media Laboratory and Department of Urban Studies and Planning are developing a transparent display that doesn't entirely block incoming light. The group is adapting a commercially available film used in electronic window shades, a high-tech alternative to blinds or curtains that lightens and darkens when electricity is applied and removed. The display will be a matrix of small separate pieces of the film. A grid of tiny wires will connect the pieces to a computer, which will be able to compose letters and figures in gray-scale patterns. Because the film at its darkest blocks only 40 percent of incoming light, and because only some of the pieces in the matrix will be darkened at any given time, people sitting behind the display will still be able to see out. Project coordinator Carlo Ratti says the technology might be seen on the streets within a year.