Changeable display apparatus

Apparatus for displaying intelligence in groups of intelligible symbols such as alphabetic and/or numerical symbols and the like, which comprises, in combination:

• a. A multiplicity of similar modules mounted adjacent each other in rows and columns and each adapted to selectively display at least one of said symbols, said multiplicity of modules presenting a substantially continuous viewing area, in which
• b. each module comprises a plurality of individuallly changeable display elements assembled in multiple rows and columns in the module and wherein each element comprises a hollow housing consisting primarily of a pair of interchangeable and similar housing parts having a common plane base and adapted to be assembled on a diagonal plane perpendicular to said base to present an essentially square viewing face except for slight truncations at corners to provide access to mounting bolts or equivalent in said base,
• c. a rotatable face piece pivotally mounted in each of said housings adapted to present selectively a relatively visible or light-showing face or a relatively non-visible or dark face, in which each face piece incorporates a permanent magnet, and
• d. an electromagnet mounted within each said housing and comprising an iron core and a coil for selectively rotating said face piece in response to control signal from an electric power source, whereby selected ones of said face pieces in a module are turned to display an intelligible symbol in said module.