https://github.com/search?&q=qart for a few different implementations, and some advancing the theory.
https://github.com/vitrun/qart - cloned from original source
https://github.com/chinuno-usami/CuteR - picture with a bit of data dither
https://github.com/scola/Qart - Android app
https://github.com/kciter/qart.js - javascript version, browser or NPM
https://github.com/search?&q=qart for a few different implementations, and some advancing the theory.
https://github.com/vitrun/qart - cloned from original source
https://github.com/chinuno-usami/CuteR - picture with a bit of data dither
https://github.com/scola/Qart - Android app
https://github.com/kciter/qart.js - javascript version, browser or NPM