A recent visit to a 2 stroke thread reminded me of this invention, the orbital.
https://en.m.wikipedia.org/wiki/Sarich_ ... loured.png
https://en.m.wikipedia.org/wiki/Sarich_ ... loured.png
"The engine, which produces very high revs, has eight moving parts in the six-chambered version depicted in the patent application, plus valves for each chamber. It can supposedly be powered by compressed air or steam[3] and can be run as a pump."
Are there any other non reciprocating designs?