If someone wants to collab, I've been writing various codes around it: https://gitlab.com/bss03/grtt

Right now, it's a bunch of crap. But, it's published, and I occasionally try to improve it.

Also, Granule and Gerty are actual working implementations, tho I think some of the "magic" is in the right grading ring for the runtime, and they and more research oriented, allowing for fairly arbitrary grading rings.