guitars

As Rickenbacker knows, shape is a function of Trademarks and not Copyright. Ric maintains TM on their stuff by actively pursuing violators and suing them. Certain copyrights expire after 20 years - a relevant one would the Gibson invention "truss rods" which help keep guitar necks straight. In 1919, Gibson invented them and put them in guitars. In 1939, the copyright on the patent was lifted and their biggest competitor at the time, Epiphone, was able to put them into their guitars, leading to the Golden Era of Epiphones from around 1940-1952. Incidentally, the brothers of the founder drove the company into the ground after his death, and Epiphone was bought by Gibson in 1957 - thereby passing along to Gibson such things as the "mini-humbucker" which was found in Firebirds and Les Pauls to name a few.