Solitaire is without a doubt the most popular video game in history, mostly because it was offered pre-installed in Microsoft’s Windows operating system, but very little is known about how it all came to be.

Even though Microsoft said that Solitaire was introduced in order to teach people how to use a mouse, Wes Cherry, a Microsoft intern that was working for the company in 1988, says he actually developed the game “out of boredom” and it was offered in Windows just to have fun with it.

“I came up with the idea to write Solitaire for Windows out of boredom, really. There weren’t many games at the time, so we had to make them,” he said in a recent interview that you can watch below.

What’s more surprising is that Cherry wasn’t paid for developing Solitaire, and the game was mostly created in his free time. And a less known thing is that Solitaire also came with a secret so-called boss key that allowed players to instantly bring a fake spreadsheet on the screen whenever their bosses were around.

Bill Gates said it was too difficult to win

This feature, however, was removed by Microsoft before Solitaire made it to Windows, so it has never been available in the public versions of the game.

Microsoft co-founder Bill Gates himself tried the game before releasing it as part of Windows, and even though he liked it, the world’s richest man complained it was too hard to win when playing it.

Wes Cherry is no longer working for Microsoft, but actually working with apples, as he owns a cidery.

A modern version of Solitaire is also available in Windows 10 as Microsoft Solitaire Collection, coming with many more features than the original version created by Cherry, including achievements, Xbox Live supports, several other game modes, and touch support to be played on tablets.