Flash of genius rule is an out dated principle of patent law that a device is not patentable if it was invented as the result of trial and error rather than as a “flash of creative genius.” The standard was set in the case, Cuno Engineering Corp. v. Automatic Devices Corp., 314 U.S. 84 (U.S. 1941), where the court held that a device must not only be new and useful, it must also be an invention or discovery. If an improvement is to obtain the privileged position of a patent more ingenuity must be involved than the work of a mechanic skilled in the art. Perfection of workmanship, however much it may increase the convenience, extend the use, or diminish expense, is not patentable. The new device, however useful it may be, must reveal the flash of creative genius, not merely the skill of the calling. If it fails, it has not established its right to a private grant on the public domain. However, this rule was legislatively overturned in 1952 by 35 USCS § 103.