Copyright protects the expression of an idea but not the idea itself. Concepts, plots, procedures, processes, systems, methods of operation, principles, and discoveries are thus not copyrightable until they have been reduced to some tangible form, no matter how original they might be. Nor is everything that has been reduced to a tangible form eligible for copyright protection. Words, phrases, slogans, blank forms, phone listings, and standard calendars will not receive copyright protection without proof that the originator contributed something new to the work. However, a reproduction of an original copyrighted work constitutes a violation of copyright law. Thus, one commercial entity may not simply reproduce another entity’s phone directory without running afoul of copyright law. But each entity is free to gather the same facts and arrange them in nearly the same manner, so long as both entities invest some original labor.