When Windows 95 was being developed, executives commissioned music legend Brian Eno to develop a "piece of music" to play when the operating system started up. This music would become known as "The Windows Sound." Eno is probably most renowned* for his ambient music -- long tracks with deep sound beds and drifting melodies. But this track had to be a little shorter. Eno related the story:

The thing from the agency said, "We want a piece of music that is inspiring, universal, blah-blah, da-da-da, optimistic, futuristic, sentimental, emotional," this whole list of adjectives, and then at the bottom it said "and it must be 3.25 seconds long."

And, of course, Eno solved the problem, creating a supremely iconic sound. But when you take his micro-music and stretch it out to two and a half minutes, it becomes suspiciously like the music we hear on his ambient albums -- slow, ethereal, moody, beautiful in a very different way. So listen to it (this is a Windows 95 ad that an enterprising YouTuber slowed way down):

(You can also listen to the normal-speed version for context.)

The shortened Eno quote above isn't the full story, though. Here's the full context from an interview -- and also keep in mind that Eno composed the sound on a Mac, saying "I've never used a PC in my life; I don't like them."

The idea came up at the time when I was completely bereft of ideas. I'd been working on my own music for a while and was quite lost, actually. And I really appreciated someone coming along and saying, "Here's a specific problem — solve it." The thing from the agency said, "We want a piece of music that is inspiring, universal, blah-blah, da-da-da, optimistic, futuristic, sentimental, emotional," this whole list of adjectives, and then at the bottom it said "and it must be 3.25 seconds long." I thought this was so funny and an amazing thought to actually try to make a little piece of music. It's like making a tiny little jewel. In fact, I made 84 pieces. I got completely into this world of tiny, tiny little pieces of music. I was so sensitive to microseconds at the end of this that it really broke a logjam in my own work. Then when I'd finished that and I went back to working with pieces that were like three minutes long, it seemed like oceans of time.

* = Yes, Eno is also very well known for his work as a producer with Talking Heads, U2, David Bowie, Coldplay, you name it, as well as a brief stint with Roxy Music. But in my world, his Ambient 1: Music for Airports record is the touchstone of his music career.