[nine_k]

What listeners get is not sheet music, it's performed music.

To me it's like an artist provides a detailed plan of how to build a monument, and then certified builders actually construct it.

Of course if an artist just gives a few rough sketches, and then a civil engineer provides the detailed drawings, and the builders construct the monument by them, then the artist is a co-author at best.

I don't know how specific D. Chihuly was in his instructions. I just think that such a separation of labor is possible, when the artist does the artistic stuff, and a performer follows on with the technical execution. In an extreme case, a machine (such as a music box) can play Bach, but that machine can't play without Bach having written the notes.