I heard that Aztec writing system uses colours (and textures) as a sign. For
exemple blue is "atl" (I'm not sure) that means "precious" (a blue mountain
is a precious mountain), but it can be read also as a phonetic sign
("atl-").
I think it is almost impossible to reduce Aztec writing system in bit, for
its extreme flexibility and for its non linearity.

> (More comment)
> Considering the sophistication and variety of almost-all-monochrome
> glyphs, it seems somewhat surprising that color[u]r has not been used more
> to give meaning. With modern colo[u]r printing and displays, at least we
> now have affordable technology to support chromatographic scripts.
>
> Digging into the history of European musical notation does reveal use of
> red ink in a few instances. (Look into "hemiola", iirc.)
>
> One wonders about use of color specifically to convey meaning in old
> manuscripts other than musical.
>
> Then, of course, mechanical business machines, including many typewriters,
> had red and black ribbons, and "dot matrix" impact printers had four-color
> ribbons, developing further on color-ribbon technology. (Btw, those
> multicolor ribbons have flexible barriers to keep the inks from bleeding
> into each other. Never occurred to me until I learned about it.)