What do people think Cobalt Violet is?
The first piece reflects on the general color range that people think Cobalt Violet should be in.
What is the real Cobalt violet?
The second piece reflects on the real Cobalt Violet range according to Winsor & Newton.
The middle point is selected.
Because people mess it up with Cobalt Blue, which is indicated by the movable track and the stopper at Cobalt Blue.