[kbelder]

I'm beginning to think a FORTH coded in GOL is within our reach.

[dvgrn]

Would you be satisfied with a Lisp implementation?

https://conwaylife.com/wiki/Lisp_in_Life

That shares the impressive inefficiencies of the Quest for Tetris project, though. For something that's much more practical to run, and can be programmed to do things like print out the digits of pi in-universe, see

https://conwaylife.com/wiki/APGsembly