I vaguely recall that the sperm cell's "tail" wasn't actually a "snake like whip", that would move like a... snake, but actually a 3D spiral that's much closer

I vaguely recall that the sperm cell's "tail" wasn't actually a "snake like whip", that would move like a... snake, but actually a 3D spiral that's much closer to Archimedes' screw in both shape and mechanism of propulsion... Was I imagining that? ... As when you look at very small stuff via a microscope you're essentially losing the third dimension and everything looks flat, so if it's also mostly translucent... you see a wiggly whip rather than a rotating spiral. But I have to say "non-reciprocal movement" has a nice ring to it.