In the United States, the patentability of any invention will generally depend upon the Patent Office’s decision, initially expressed by an Examiner, as to whether the invention is useful, novel, and unobvious. These requirements are set forth in the Patent Statute. In particular, Sections 102 and 103 relate to the differences between the invention and the prior art. Section 102 requires that an invention be novel in the sense that it has not been disclosed by any single prior art reference. Section 103 requires that the differences between the invention and the prior art be such that the invention would not have been obvious, at the time it was made, to a person having ordinary skill in the art.