How can "actual reduction to practice" be demonstrated?

Actual reduction to practice is demonstrated by constructing a prototype or performing the method of the invention. This concept is fundamental in patent law because it shows that an inventor has not only conceived of the idea but has also taken tangible steps to bring it to fruition.

Building a prototype, for instance, provides physical evidence that the invention works as intended. In contrast, simply describing the invention or filing a patent application does not meet the criteria for actual reduction to practice; these actions reflect an idea or intention but do not demonstrate that the invention has been successfully realized in a practical form. Similarly, obtaining a foreign patent or filing a provisional patent application are steps in the process of pursuing patent protection but do not substantiate that the invention functions effectively in practice. Thus, constructing a prototype or performing a method is the only choice that fulfills the requirement of demonstrating actual reduction to practice.