While working examples can be helpful in demonstrating enablement, they are not always required. The MPEP 2164.02 states: "The specification need not contain an example if the invention is otherwise disclosed in such manner that one skilled in the art will be able to practice it without an undue amount of experimentation." However, the absence of working examples is a factor to be considered, especially in unpredictable or undeveloped arts. The MPEP further clarifies: "Lack of a working example, however, is a factor to be considered, especially in a case involving an unpredictable and undeveloped art." In evaluating enablement, examiners must consider all factors, not just the presence or absence of working examples. A single working example may be sufficient to enable a claimed invention, depending on the other factors and the nature of the invention. To learn more: working examples enablement patent application MPEP 2164.02 undue experimentation