I used a 3 pixel wide font extensively back on the '80s to write debug messages to Mac screens from code that could not make use of the normal Mac ROM and OS di

I used a 3 pixel wide font extensively back on the '80s to write debug messages to Mac screens from code that could not make use of the normal Mac ROM and OS display functions. At first this was when writing SCSI disk drivers for a third party Mac disk maker. Later it was when writing network drivers for a company making a SCSI ethernet interface. Then it was when working on firmware for some NuBUS cards for Mac II. I didn't want to write a full BITBLT, but I didn't want to make width + spacing be 8 pixels because even though that would be very easy it would also mean I could only have 64 characters to a line on the Mac or Mac Plus (512 x 342 display). With characters 3 pixels wide and 1 space between them you just need a simple BITBLT that only has to handle two cases. My font was 3x5. Unlike the other 3x5 fonts people have mentioned I didn't try to include lower case. Here's a sample, scaled up by factor of 4: https://imgur.com/a/I97Zi6l https://imgur.com/a/I97Zi6l The reason that there is a prominent visible symbol for newline is because when the debug print got to the bottom of the screen it would wrap back to the top. The prominent newline let you tell which characters on the line came from the latest print on that line.