Priva-Lite is a registered trademark for a high-tech (and very expensive) glass that can be switched between transparent and opaque. I imitated this function with low-tech installation. In an abandoned shop with a very big window front I placed a fog machine, which was filling the whole space with fog. The visitors could not enter the room; the installation was only visible from outside. When the fog became very thick the window front looked like an opaque glass. Then it took four hours for the fog to disappear and the glass looked more and more transparent as if it was a slow motion switch from opaque to transparent and backwards. This process was permanently repeated.