It's the how many sides of a coin question. There is only a right answer in the context, dimension and design of said coin. Two? 3? 5? 1?

Still just a three dimensional object. 1D would be invisible. Humans do not create 5D objects. How many can visualize 5D?

And yes, Color Theory :)

Helmholtz managed to trap color vision into the 3D RGB world. Theory does not accommodate tetrachromatic women.

Good point! And, why I enjoy the edge ideas within the theoretical science. That anomaly becomes an opportunity for deeper study.

Instead of RGB, it should be RYV (Red, Yellow, Violet). Violates Helmholtz theory of primary colors, but is more accurate.