Colour swatch clouds

Google tells me that cloud colour is down to Mie Scattering, where clouds scatter all wavelengths of light equally to produce mostly white. Variations on the whiteness depend on where you're seeing the cloud from and the thickness of the cloud.

A series of huge dispersive prisms is arranged to break down the light arrays into beams of differing wavelengths and turn the clouds into a random celestial display to rival the Northern Lights.