Prior to the release of the Macintosh 128K, the first Macintosh computer, marketing executives at Apple feared that including a game in the finished operating system would aggravate the impression that the graphical user interface made the Mac toy-like. More critically, the limited amount of RAM in the original Macintosh meant that fitting a game into the operating system would be very difficult. Eventually, Andy Hertzfeld created a Desk Accessory called "Puzzle" that occupied only 600 bytes of memory. This was deemed small enough to be safely included in the operating system, and it shipped with the Mac when released in 1984. With "Puzzle"—the first computer game specifically for a mouse—the Macintosh became the first computer with a game in its ROM, and it would remain a part of the Mac OS for the next ten years, until being replaced in 1994 with "Jigsaw", a jigsaw puzzle game included as part of System 7.5.