506. Variation.

A variation in scale or degree in an article or process may form subject matter if it has brought about new and useful results1.

Although it cannot be laid down as a rule of law that there is no patentable subject matter in printing or drawing on articles signs that facilitate their use, the courts have generally refused to recognise the validity of patents having such an object2. Similarly, variations in the shape of articles to adapt them for use on a particular machine do not generally form patentable subject matter, even though the machine itself is novel and constitutes