Nearly three decades after Apple Computer introduced the Macintosh, a pair of incredibly rare Mac prototypes have been discovered and restored to working order.

The computers, known as Twiggy Macs because they used the same 5.25-inch Twiggy floppy disk drive found in Apple’s doomed Lisa, were tracked down and painstakingly brought back to life by Adam Goolevitch, a vintage Mac collector, and Gabreal Franklin, a former Apple software engineer.

“Throughout the past 15 years, I have heard stories of and researched the fabled ‘Twiggy Macintosh’ computer,” Goolevitch told Cult of Mac in an email. “It was a thing of myth and legend — like a unicorn.”

Locating these Macs was the first step, but getting them to work was the real challenge. Goolevitch and Franklin embarked on an all-out effort to resurrect these long-lost pieces of Macintosh history.

Now two Twiggy Macs have been returned to life in full working glory. They are — without a doubt — the oldest Macs in the world. With auction prices for Apple-1 computers nudging upward toward the half-million-dollar mark, these incredibly rare prototypes — which look a lot like something you might find at a garage sale — could prove priceless. Here is the story of their amazing resurrection.

The famous Macintosh Picasso logo was developed for the introduction of the original 128k Mac back in 1984. A minimalist line drawing in the style of Pablo Picasso, this whimsical graphic implied the whole of a computer in a few simple strokes. It was an icon of what was inside the box, and became as famous as the computer it represented.

The logo was designed by Tom Hughes and John Casado, art directors on the Mac development team. Originally the logo was to be a different concept called The Macintosh Spirit by artist Jean-Michel Folon, but before the release Steve Jobs changed his mind and had it replaced by the simple and colorful drawing by Hughes and Casado. It’s been beloved ever since, and the graphic style has endured across decades.