It isn't just prior art. The principle of engineering known as rounded corners was forced upon the makers of Liberty Ships during the early 1940's. Previous attempts to weld vessels together with large square holes in them came apart in the Atlantic.
The process of making rounded windows especially for ships probably goes back to the time of Noah but was largely forgotten just in time to make the Comet Britain's epic Fail of the 1950's
I would have thought the Sorks would know about ship building principles or don't they apply to mobile phones over there?