IDK...perhaps a time limit to implement for the patent to be registered?
You can hold a Design Patent for 2 years, after which if you haven't achieved a practical prototype, you lose patent rights.
Maybe something along the lines of a "Provisional Patent Application" (which lasts for 1 year)?
Blog That A-Ha Moment Larry Desjardin 11 comments Have you ever had an a-ha moment? Sure, you have. The Merriam-Webster dictionary defines it as "a moment of sudden realization, inspiration, insight, recognition, or ...