The idea of transforming has been around for a while as the below video of the Roentgens' Berlin Secretary Cabinet proves. What appears to be a large clock is really a desk with a whole lot of built in secrets activated through key turns and spring releases. The cabinet was built sometime in the late 18th century and owned by King Frederick William II of Prussia by Abraham and David Roentgen. The desk is currently on display at New York's Metropolitan Museum of Art.