Apple quietly licensed certain design patents to Microsoft, it's been revealed as part of its patent case against Samsung.
According to the company's patent licensing director Boris Teksler, Microsoft licensed Iphone and Ipad design patents from Apple as part of a gentleman's agreement that Microsoft wouldn't copy Apple devices too closely.
"There was no right with respect to these design patents to build clones of any type," he said, according to Reuters.
The deal's believed to have been struck as long ago as 1996, when Apple didn't dominate the industry as it does now, and may explain why Apple and Microsoft have never crossed swords in court over patents, when so many other industry players have become involved.
The disclosure forms part of Apple's attempt to argue that Samsung, too, should be paying for similarities between its own products and Apple's. Indeed, it claims that Samsung's are blatant copies and go further than anything Apple would ever allow.
"All these patents are in Apple's unique user experience, and not ones we would license," said teksler.
It was also revealed that Samsung turned down a 2010 offer from Apple to license various patents - at the rather eye-watering cost of $30 per smartphone and $40 per tablet. Apple filed its lawsuit the following April.
Apple and Samsung are expected to present their closing arguments in court next week. Apple's asking for $2.75 billion in damages.