Interesting observation, Peter. Perhaps you are describing artists whose messy mental/emotional processes take place in their media instead of in their heads. da Vinci seems to have been particularly fearless in that regard. He was not afraid to walk away from a piece and leave it unfinished if he got interested in something else, come back to it later, or just leave it dangling, sketch-marks exposed, for posterity.

I suppose that would be difficult to undertake in an unforgiving medium, such as stone-carving, though.

E.