A patent for an invention is the grant of a property right to the inventor, issued by a Patent Office. Generally, the term of a new patent is 20 years from the date on which the application for the patent was filed in the Patent Office or, in special cases, from the date an earlier related application was filed, subject to the payment of maintenance fees. Patent grants are effective only within the a country in which patent has been filed. Under certain circumstances, patent term extensions or adjustments may be available. The right conferred by the patent grant is, in the language of the statute and of the grant itself, “the right to exclude others from making, using, offering for sale, or selling” the invention in a country or “importing” the invention into the country. What is granted is not the right to make, use, offer for sale, sell or import, but the right to exclude others from making, using, offering for sale, selling or importing the invention. Once a patent is issued, the patentee must enforce the patent without aid of the Patent Office. There are three types of patents: 1) Utility patents may be granted to anyone who invents or discovers any new and useful process, machine, article of manufacture, or composition of matter, or any new and useful improvement thereof; 2) Design patents may be granted to anyone who invents a new, original, and ornamental design for an article of manufacture; and 3) Plant patents may be granted to anyone who invents or discovers and asexually reproduces any distinct and new variety of plant.