This is a prototype cartridge that never saw official release. The program allowed the user to compose music over a three-octave range using the controller to enter musical notes for replay over the TV speaker. Development started by Bally before 1979 as two cartridges but never released. In 1982, development continued with completion of a 2,000-baud tape interface, instructions, and controller overlay. Final work was completed in 1985 with the engineering of the tape interface circuit boards.