Dear Ignakano, The concept of puzzle rings is already very old. Bram's design is special because of its specific weaving pattern, which is quite different from the classic many-band weaving. Bram Cohen design is also significantly harder than the classic designs. Oskar

Not sure when Bram Cohen had the idea, but if it was after 1997, I know for a fact that the idea was not new. Back in 1997, I bought two 7-band ring from Orb Silversmiths (we use them as wedding bands), and they had rings up to 17 bands, if I recall correctly. They seem to have gone out of business, but http://www.puzzlering.com/ has quite a few designs, although not the exact 7-band models we got.