These earrings are made of concentric Darrieus turbines, so they'll spin when you blow on them (once you loosen them up a bit). They are quick and easy to print, unlike most of my designs. Just add your own ear wire to complete them. An 8mm jump ring fits nicely in the holes at the top.
This is designed to print the walls exactly two 0.4mm paths wide, no infill needed. I have printed it at half scale as well, but most slicers fail. Other scales will probably not come out well.