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PrusaSlicer Scarf Joints
The release notes for PrusaSlicer 2.9 mention the addition of scarf joints on outer perimeters. Smooth joints seem like a Good Idea™, so I turned it on for comparison with a recent object:

Double Gear fidget toy – scarf vs normal Those are flipped from the as-printed orientation: the orange ring builds upward, starting with two concentric threads on the platform.
The normal aligned joint is on the right above, with a closer look here:

Double Gear fidget toy – normal joInt The scarf joint has a offset between layers:

Double Gear fidget toy – scarf joint The PrusaSlicer visualization shows the effect, looking up from below the platform:

Double Gear fidget toy – scarf joint visualization The blue PETG-CF parts have no visible seams anywhere with either setting, probably because the stuff swells slightly and obliterates any subtle differences.
Scarf joints don’t make much difference for a fidget toy, but should improve the outcome for more critical circular / spherical models.