I ran across this shape in another model I was working on but stopped (partly due to this shape.)
I’m almost done making a corkscrew wine opener like the one here
At the top of the center shaft where the notches stop and the bottle opener “head” piece is, there’s a tapered section.
It starts circular, tapers to flat, but at the same time creates that parabola shape in its taper.
I’ve tried using parts of circles as well as moving individual verts around but I’m not really getting anything desirable.
I tried to find a picture of the shape in another context but don’t really know what it’s called. I’ve seen it before in mechanical arm connector/multi-axis rotation pieces.
Let me know if you’re still unsure about what I’m talking about