I had always
understood patents to be about the mechanism of the device, not it's effect. E.g., a particular mouse trap design, not the idea of catching mice.
But what do I know? Squeak blogger
Torsten turned me on to
this article about some courtroom pirates suing Apple over the User Interface in their latest operating system release. The original patent was for an old Xerox UI implemented in Interlisp-D, and now owned by a holding company.
Apple's Tiger operating system isn't implemented in Lisp. Do you suppose the lawyers are basing their argument on
Greenspun's Tenth Rule?
If I recall, Xerox PARC once litigated against Microsoft for the same thing - and won a huge settlement from them.