The Apple Lisa was not, by nearly any definition, a hit product. Released in 1983, the ambitious but flawed machine was instantly overshadowed by Apple’s follow-up, the 1984 Macintosh — which helped cement the computer as a fixture in homes and offices worldwide.

But the design language of the Lisa is the design language of modern computers. It was one of the first machines to use the metaphor of a desktop, including things like folders, icons, and application windows that mimicked sheets of paper. Apple drew inspiration from outside sources, particularly the Alto, a groundbreaking machine developed at the Xerox Palo Alto Research Center. But it iterated on the formula with obsessive user testing that adapted to first-time users’ intuitions. The result is something that, 40 years later, feels strange and familiar at the same time.

There’s a dwindling number of Lisas in the world, but I was lucky enough to get my hands on one, thanks to a generous (and prolific) Apple hardware collector. It was a chance to explore what made the Lisa so special... while, admittedly, getting an inkling of why so many people picked a Mac instead. It’s some of the most fun I’ve had on a computer for years, and you can check out the video above to take a tour of it.