The component of the Macintosh hardware that had the longest lead time was the hard tool that molded its distinctive plastic case. After tweaking the case design for more than six months and building a small production run of 50 units with a soft-tooled case, the final design was ready to go out for hard tooling toward the end of February 1982, so we could meet the ship date that we were aiming for at the time, which was January 1983.
The Mac team had a complicated set of motivations, but the most unique ingredient was a strong dose of artistic values. First and foremost, Steve Jobs thought of himself as an artist, and he encouraged the design team to think of ourselves that way, too. The goal was never to beat the competition, or to make a lot of money; it was to do the greatest thing possible, or even a little greater. Steve often reinforced the artistic theme; for example, he took the entire team on a field trip in the spring of 1982 to the Louis Comfort Tiffany museum, because Tiffany was an artist who learned how to mass produce his work.
Since the Macintosh team were artists, it was only appropriate that we sign our work. Steve came up with the awesome idea of having each team member’s signature engraved on the hard tool that molded the plastic case, so our signatures would appear inside the case of every Mac that rolled off the production line. Most customers would never see them, since you needed a special tool to look inside, but we would take pride in knowing that our names were in there, even if no one else knew. (from Folklore.org by Andy Hertzfeld)