It's fortunate that we mostly have 3 categories of cones and also 3 spatial dimensions. Notice that magenta is a vertex (of 8 vertices) in the cube, along with Yellow and Cyan too.
How the particular space (of activation to the 3 categories of cones) is carved out by that cube is something we engineered, and in fact is different across different printing and display technologies.
It's fortunate that we mostly have 3 categories of cones and also 3 spatial dimensions. Notice that magenta is a vertex (of 8 vertices) in the cube, along with Yellow and Cyan too.
How the particular space (of activation to the 3 categories of cones) is carved out by that cube is something we engineered, and in fact is different across different printing and display technologies.