Where an invention is obvious or not depends on the state of the art and the skills of an ordinary person in the art. This means that obviousness is measured based on the knowledge of an average person who is familiar with the technology related to the invention. The knowledge of an average person is based on prior art. Prior art is any evidence that an invention was already publicly known or available, in whole or in part, before the effective filing date of a patent application. Patents, academic papers, public offers for sale and public use of the invention are some examples of things which qualify as prior art. Secret uses of an invention or publications that do not detail the invention enough to allow an ordinary person in the art to recreate the invention do not qualify as prior art.