What is "baguenaudier"

Baguenaudier (also known as the Chinese Rings, Cardan's Suspension, Cardano's Rings, Devil's needle or five pillars puzzle) is a disentanglement puzzle featuring a loop which must be disentangled from a sequence of rings on interlinked pillars. The loop can be either string or a rigid structure.

It is thought to have been invented originally in China. The origins are obscure. The ethnographer Stewart Culin related a tradition attributing the puzzle's invention to the 2nd/3rd century Chinese general Zhuge Liang. The name "Baguenaudier" is French for "time-waster". It was used by French peasants as a locking mechanism.

Variations of this include The Devil's Staircase, Devil's Halo and the Impossible Staircase. Another similar puzzle is the Giant's Causeway which uses a separate pillar with an embedded ring.