Proceedings of the 14th Annual Fall Workshop on Computational Geometry
One of the open problems posed in  is: what is the minimal number k such that an open, flexible k-chain can interlock with a flexible 2-chain? In this paper, we establish the assumption behind this problem, that there is indeed some k that achieves interlocking. We prove that a flexible 2-chain can interlock with a flexible, open 16-chain.
Glass, Julie; Langerman, Stefan; O'Rourke, Joseph; Snoeyink, Jack; and Zhong, Jianyuan K., "A 2-Chain Can Interlock With a k-Chain" (2004). Computer Science: Faculty Publications, Smith College, Northampton, MA.