Over time, subtle changes were made to the packaging used by Mattel (and later INTV Corporation) to deliver Intellivision (and eventually M-Network games). Once Mattel started making the M-Network games for the Atari VCS (a.k.a. Atari 2600), the cartridge case was modified to have a couple of slots in one end. The M-Network "adaptor" could then be snapped onto the end. The following images chronicle the evolution of the primary Intellivision cartridge case.

I will not attempt to chronicle here all the various ways, fonts, and locations that the Mattel copyright was put on the cartridges. Suffice to say, there are many.