Design-wise, and to the best of my understanding, the Steiner Phase Shifter is a fairly straight-forward four-stage phaser (180 deg. per stage). As an added bonus, it features voltage control, and a wet-dry crossfade.
Lots of diodes and op-amps (LM741s to be inserted later)! It is interesting to me how some of the Synthasystem designs utilize opamps, while many don't use them at all. They are certainly a feature of the "modern" modular synth (whatever that means), particularly for input and output buffers. Presumably their availability was limited when Nyle was designing the main/core modules, but were more available when he was designing others. But, I don't know for sure!
Anyhow, I'm really looking forward to hearing this in action!