If you’ve ever spent hours playing Microsoft Windows solitaire, you have a lowly intern to thank. During the summer of 1988, Wes Cherry was interning at Microsoft and noticed that the company's computers didn’t have virtual card games like the ones included on his Mac. He set out to change that.

On his own time, Cherry wrote code to create solitaire (also known as Patience and Klondike). His then-girlfriend, Leslie Kooy, also pitched in, designing some of the cards: “I did the weirder ones: rainbow shell, haunted castle, beach scene, robot, hidden ace,” she said. Designer Susan Kare was responsible for the rest of the deck.

After he finished the game, Cherry left it on a shared server for others to use. “At the time there was an internal ‘company within a company’ called Bogus software,” he wrote on Reddit. “It was really just a server where [a] bunch of guys having fun hacking Windows to learn about the API tossed their games.”

A program manager for Windows 3.0 eventually spotted the game on the server and decided to add it to the official install. The game was released in May 1990 and it became an instant classic—and the most popular way to kill a little time at the office.

Unfortunately, the developer—who now owns and operates a cidery on Vashon Island in Washington State—didn’t receive a dime, though he says that doesn't bother him: “It was made clear that they wouldn't pay me other than supplying me with an IBM XT to fix some bugs during the school year—I was perfectly fine with it and I am to this day.”

Cherry knew you were going to use his program to procrastinate, by the way. He even included a “boss-key” that users could hit to quickly switch to a more work-friendly screen. “Microsoft made me remove that," he said. (Too bad—the boss-key could have prevented Edward Greenwood from losing his job in 2006, after New York Mayor Michael Bloomberg saw the program open on Greenwood’s screen.) Cherry also used the program to procrastinate, though not exactly in the way you and I do: “I wrote solitaire instead of studying for finals in college.”