I spent a hot second last year thinking about sparklines in a terminal, and it seemed to me that unicode could use some more glyphs to improve this situation of treating a single glyph as a modest array of pixels. I don't know what I googled for, but for some reason I found only about 1/3rd of the characters listed in the final two lines of

http://tamivox.org/dave/boxchar/index.html

Unless I'm wrong about your demo, it seems like you are using some of these? There's a 2x2 pixel grid, and some characters that would be good for bar charts, both horizontal and vertical, and also with negative numbers. That's better than I thought we had, but not a big palette to work with.

Are you aware of any proposals to expand the pixel art capabilities of Unicode? Grids have the problem of requiring 2^(X x Y) characters to represent all states, but diacritical marks don't have that scaling problem. For example it would take 64 characters to represent a 2x3 grid of all on/off states, whereas a 6x8 grid of rectangular diacritical marks would only take 48 glyphs.