[count-your-change]

That sounds good but that cylinder has to hit the the mark with virtually perfect alignment despite gear wear and manufacturing tolerances.

A handmade model or one in a video simulation is fine but other than a novel design it's hard to see any advantage over a cam engine or multivalve conventional engine.

[TigersEye]

You should watch the video of the one they have up and running on propane. It’s not hand-cranked or a video simulation.