We study collections of linkages in 3-space that are interlocked in the sense that the linkages cannot be separated without one bar crossing through another. We explore pairs of linkages, one open chain and one closed chain, each with a small number of joints, and determine which can be interlocked. In particular, we show that a triangle and an open 4-chain can interlock, a quadrilateral and an open 3-chain can interlock, but a triangle and an open 3-chain cannot interlock. © 2003 Elsevier Science B.V.
Demaine, E. D., Langerman, S., O’Rourke, J., & Snoeyink, J. (2003). Interlocked open and closed linkages with few joints. In Computational Geometry: Theory and Applications (Vol. 26, pp. 37–45). https://doi.org/10.1016/S0925-7721(02)00171-2