A patent application (perhaps apocryphally) filed on a non-working version of an invention, to confuse and mislead would be copiers. The most cited example of such an application was filed by a well-known magician John Nevile Maskelyne and his collaborator John Algernon Clarke for an Actuating Automaton Mechanism on 14 May 1875 (Application 1804.) It is widely held that this patent application was intended to obfuscate how Maskelyne’s famous illusion Psycho, a Bridge or Whist (the card games) playing automaton worked. See Joke Patent