“This invention relates to new and useful improvements in an aeroplane of rooster shape.” Well, all right, then. Angel Mateo’s 1930 patent application is remarkably thorough — the wings even flap — but nowhere does the inventor explain why he thinks the world needs such a thing. “The propeller is depended upon to accomplish most of the flying of the device and the wings to assist in the flying and also to simulate a flying rooster.” Perhaps, like a poem, it provides its own reason.