Rings is a resonator. Feed it with an audio signal and the built-in pluck sound will become madness. I have Rings and it's definitely a favorite but in a basic setup I would start with 2 analog VCO with FM and Sync Input and a wave folder as my main sound source.

Distorted Rings
-- defragmenteur

I've tentatively settled on a second true VCO but haven't considered anything in terms of waveshapers. Off to do more googling, thanks. At specific recommendation to start my searching?