Matt Sarnoff builds homebrew computers and electronics projects and writes up the hardware, PCB design, and display tricks involved.
HN commenters link it mainly for Millitext, a tiny-text technique that uses subpixel rendering, and one calls it only visible with a magnifier or macro lens.
this is actually 4×4 if you're counting pixels needed on the output device instead of rom space needed; another, more comprehensive font of the same size is https://simplifier.neocities.org/4x4
the same problem happens with the public-domain 'tom thumb' font pushfoo linked in https://news.ycombinator.com/item?id=38800409. it is actually 4×6 (24 output pixels) but claims to be 3×5
it can be accessed despite tls problems at http://web.archive.org/web/20230828193815/https://robey.lag.net/2010/01/23/tiny-monospace-font.html but says 'Please do not post this article to Hacker News.'
my own 4×6 font is demonstrated at http://canonical.org/~kragen/sw/dofonts-1k.html, where it fits into a 1024-byte web page along with all the logic needed to render ascii text with it; but the proportional font i used in http://canonical.org/~kragen/bible-columns (rendered with http://canonical.org/~kragen/sw/netbook-misc-devel/propfontrender.py) is at http://canonical.org/~kragen/sw/netbook-misc-devel/6-pixel-1-bit-proportional-font.png and is slightly smaller; it averages 21.5 pixels per character. this is more than anders de flon's so-called 3×3, which is 16 pixels per character, but it supports the full character set, if you think ascii is the full character set anyway. so does simplifier's 4×4 font
i think you could do better by using grayscale for antialiasing, and as rafabulsing pointed out, matt sarnoff's millitext http://www.msarnoff.org/millitext/ uses subpixel antialiasing to get…
I "discovered" this about 2 years ago. It's really only visible with a magnifying glass or camera with a good macro lens.
http://msarnoff.org/millitext
I also made a web-based generator:
http://msarnoff.org/millitextgen
The rationale is that you can control the position of the visual parts that make a letter by changing the color of the larger pixel.
http://www.msarnoff.org/millitext/
https://millitext.gk.wtf/
1x5 can also work if you take advantage of subpixel rendering https://www.msarnoff.org/millitext/
See Millitext: http://www.msarnoff.org/millitext/
Direct link: https://www.msarnoff.org/millitext/