[gwern]

> Edit: IvyMike and ryanhuff brought my attention to the 20 year maximum term of patent. It is surprising that Steinway's competitors still are unable to match the quality of sound.

Not necessarily. Patents only need to describe enough to be enforceable, they don't have to include any of the subtle details which are necessary to make things tick. A famous example of this was all the patents filed by the famous German pharmaceutical & chemical giants in the USA to protect their cutting-edge processes: the patents worked very well to protect their IP, and then WWI came and the salivating competitors got the German patents seized - and couldn't figure out how to do the things, because the patents had left out critical details.