It's not quite the same as Lego blocks. As far as my knowledge goes - assuming that this is the same as harmonic decomposition - if you use enough higher and higher harmonic modes you can reproduce the original. If we are talking about harmonic analysis and decomposition/transformation here, then I do know what I am talking about because I use it extensively in my day job (which has nothing to do with audio).

I am however uncertain if a harmonic reconstruction of a copyrighted work to extract certain elements of that work (a certain set of harmonic modes) results in a new work in which the original author has no copyright claim. I would have assumed that there would be something written about this legal subject. However I find nothing on the web. So I have no way of knowing if this is legal or not. Well, apart from lots of opinions

Regards,

Edward