Patents grant an inventor the right to exclude others from producing or using the inventor's discovery or invention for a limited period of time. In order to be patented an invention must be novel, useful, and not of an obvious nature. There are three types of patents: a) "utility patent" which includes a process, a machine (mechanism with moving parts), manufactured products, and compounds or mixtures (such as chemical formulas); b) "design patent" which is a new, original and ornamental design for a manufactured article; and c) "plant patent" which is a new variety of a cultivated asexually reproduced plant.