[johnfn]

ChatGPT does almost as good as one could imagine:

> If you are asking about the difference between two instances of the color blue, it is possible that you are looking at two shades of blue that are slightly different from each other. The color blue can come in a wide range of shades, from pale and subdued to deep and vibrant. Some shades of blue may appear more greenish or purplish, while others may appear more true blue. The specific shade of blue that you are looking at may depend on a variety of factors, including the lighting, the surface or material on which the color is applied, and the specific pigments or dyes used to create the color.