Fidget Rings

They are some spinning rings I made and have a gap of 0.4mm. I made them to be thinner sideways, so they don't limit the neighbor fingers movements. It can come out stuck, but you can free them with a few little knocks on a surface. There is an inverted version so you can paint the lines like the image. Paint all the surface (bumps and grooves) and remove the excess with a cloth before it dries.