While Apple and Samsung continue dishing dirt at the patent trial of the century, Apple patent licensing director Boris Teksler reveals yet another interesting fact-- an "anti-cloning agreement" the company has with Microsoft.

The patent trial has Apple accusing Samsung of copying not only iPhone and iPad industrial design (a rectangular screen with rounded corners) but also the iOS UI.

But what is an "anti-cloning agreement"? The secretive Apple has a patent cross-license agreement with no other than Microsoft... only on the condition the 2 companies will never imitate each other's product designs. A copy of such an agreement between the 2 companies dating August 1997 is actually available online.

The patents in question cover design, form factor and also what Apple calls the "unique user experience."

"We took special prohibitions from both parties so there is what I term an 'anti-cloning' provision... so we couldn't copy each other's products," Teksler says. "There's a clear acknowledgement that there's no copying."

No wonder Microsoft's Windows Phone interface looks so different to anything on the market.

Reuters reports Apple reached out for a similar agreement with Samsung back in 2010... but negotiations clearly failed.

Apple also claims over 25% of Samsung US smartphone and tablet sales (worth $30.4 billion) are the result of either copying iDevice designs or the infringment of other Apple patents, and demands up to $2.75bn in damages.

Go Apple Expert Shines Light on Samsung Sales in US (Reuters)