Piano overtones are normally off-pitch (in a sense), and guitar too, to a lesser extent. I would imagine organ overtones to be highly dependent on the design of

Piano overtones are normally off-pitch (in a sense), and guitar too, to a lesser extent. I would imagine organ overtones to be highly dependent on the design of the specific instrument, but I'm guessing they are largely more harmonic. https://en.wikipedia.org/wiki/Stretched_tuning https://en.wikipedia.org/wiki/Stretched_tuning