PyPi: https://pypi.org/project/plakativ/

k2pdfopt is an alternative with a billion useful options:

https://www.willus.com/k2pdfopt/

As far as I can see, k2pdfopt has many options for reflow, but none to posterise? Let alone posterise for non-rectangular arrays of printed output, like TFA?

(banner(6) sends its greetings from the 1970s. https://www.freebsd.org/cgi/man.cgi?query=banner&sektion=6 )