This cube visualizes which of the 16,777,216 colors have assigned names

See the GitHub repository[0] for more information. Note that [R,G,B] vectors span 256 x 256 x 256 = 16,777,216 possible colors. This repository has named 16,880 of them, which is around 1 in 1,000. For every 1,000 colors, 999 still need names!

Or do they? How many colors can simply be represented as "a lighter version of X" where X is a named color? How many colors can we "eliminate" this way? Also, of these 16,880 named colors, how many of them are lighter or darker versions of the others?

[0] https://github.com/meodai/color-names