>Narrower 4x5 and 3x5 dimensions are possible, but would require sacrificing the M, dotted zero, and reduce U/V/Y distinctiveness.

I think 3x5 works well enough:

https://robey.lag.net/2010/01/23/tiny-monospace-font.html

Idk why maybe my font-size on this screen is too small but when I glanced at that title I read: "Sex Pistols font for tiny screens" haha

When I was building the layouts for my e-paper calendars , I needed pixel fonts due to the lack of grayscale on the display. It was surprisingly hard to find them - especially with customers asking for Cyrillic characters.

Small g is unreadable. I obviously know the alphabet and despite that it took quite some time to understand what letter is that.

   xxx
  x   x
  xxxxx
      x
  xxxx

      xx
     x x
      xx
    x  x
     xx

Fonts like this are also great for huge screens like LED signage. Big pixels and very low resolution, so logically a tiny screen.

This is awesome!

I could almost fit an entire 80x40 terminal on my watch face!

Oh cool, I have to try these fonts on my amber CRT getting commands from an Elm webapp ([demo](https://youtu.be/M9Q5tFPtGaA?t=121), [code](https://github.com/Janiczek/crt-esp32-elm/tree/main/vdom/)) - there's not a lot of real estate in a 400x240 NTSC resolution. But the scanlined rendering has so much charm!

EDIT: realized a better demo for this discussion would be the photos I took of all the tiny bitmap fonts I had converted to the C array style at the time. Thread has more but here are my favorites: https://bsky.app/profile/janiczek.cz/post/3mh25atboz224

Looking at the screenshots shows why there's a reason 5x7 is the "standard" for tiny legible fonts that cover all of ASCII, e.g. as found in character LCD displays:

https://en.wikipedia.org/wiki/HD44780_(integrated_circuit)

The 3x2 is fascinating, it's the same resolution as braille, albeit rotated 90 degrees. I wonder if this could become a braille-like system that's both visually and finger-readable.

Note: there are repeat glyphs here like c and o, though the example actually uses a different c somehow. But perhaps repeats are ok given context.

I developed a font with a similar resolution that was not nearly as legible for my Pi Zero with an e-ink screen many years ago. It allowed for similar tooling such as the flipper zero and esp32 marauder projects. I should fire that project up and implement this font…