This is such a good judgment by the Court of Apeal:
General ideas and structures behind computer games and programs can be copied as long as the source code and graphics are not, the UK's Court of Appeal has ruled.
The judgment upholds an earlier High Court ruling in a case involving three computer games simulating pool. Under UK copyright law and EU Directives, the court ruled that the ideas behind the games cannot be protected by copyright, because copyright does not protect general ideas.
"Merely making a program which will emulate another but which in no way involves copying the program code or any of the program's graphics is legitimate," said Lord Justice Jacob, who gave the Court's ruling.
This really gets to the heart of what a program is - code - and where the originality lies - in the details of its coding, which is protected by copyright, not patent law.
Fab, M'Lud.