> Perhaps you need to somehow create a rapidly changing filter glass of all different wavelengths. Purely hypothetical. Monochromatic colors are just a tiny, t

> Perhaps you need to somehow create a rapidly changing filter glass of all different wavelengths. Purely hypothetical. Monochromatic colors are just a tiny, tiny sliver of the perceptible color space. They're not even the boundary of it, they're such a small part of perception that they're only a part of the boundary. In the CIE model, the curved part of the boundary represents monochromatic colors. The surface itself is not monochromatic, and neither is the straight boundary (line of purples). And that model is a simplification in and of itself.