Found this design on instructables:https://www.instructables.com/id/Rope-Ring-Puzzle/ by user mtairymd. I made one with wooden parts with only the ring 3d printed. Not everyone with a 3d printer has access to woodworking tools so I made one entirely using 3d printed parts. The parts are all very simple to design but i since I already made them I might as well share them. You'll need to print 2 of the beads. I used 60cm of paracord but any similar sized cordage will do (approx 4mm in diameter).

For setup and the solution go to https://www.instructables.com/id/Rope-Ring-Puzzle/

EDIT: So after uploading this i found https://www.youmagine.com/mtairymd/designs
It's essentially the same but I will leave my design up and check that he's ok with it.