Unwrapping Chains
  A loop of chain can move along its own tangents, maintaining a steady shape. An open-ended chain undergoing a nontrivial motion must change its shape. One consequence is that chains pulled around objects will fail to follow the contours of the objects, unwrapping themselves instead. This short note accompanies a fluid dynamics video submission (83068) to the APS DFD Gallery of Fluid Motion 2012. 
A. D. Cambou, B. D. Gamari, E. Hamm, J. A. Hanna, N. Menon, C. D.   Santangelo, L. Walsh
physics.flu-dyn