History of Loosen the Rings
Ring puzzles are old - the Chinese rings were described around 1500; this flat version with gaps is new.
Old ring puzzles
Puzzles in which rings have to be freed are old. The best known, the Chinese rings, is described by Luca Pacioli in his manuscript De viribus quantitatis around 1500 and was printed in 1550 by Girolamo Cardano; in China it is first mentioned in the early 16th century. Where it was invented is not known.
A new puzzle on paper
Loosen the Rings was made for PaperGames: flat rings with a gap, drawn from above, that turn like gears. Because a ring slips off only where its neighbour lies on top, the weave of the drawing is part of the puzzle.