Discrete & Computational Geometry

, Volume 12, Issue 3, pp 367–384

Objects that cannot be taken apart with two hands

  • J. Snoeyink
  • J. Stolfi

DOI: 10.1007/BF02574386

Cite this article as:
Snoeyink, J. & Stolfi, J. Discrete Comput Geom (1994) 12: 367. doi:10.1007/BF02574386


It has been conjectured that every configurationC of convex objects in 3-space with disjoint interiors can be taken apart by translation with two hands: that is, some proper subset ofC can be translated to infinity without disturbing its complement. We show that the conjecture holds for five or fewer objects and give a counterexample with six objects. We extend the counterexample to a configuration that cannot be taken apart with two hands using arbitrary isometries (rigid motions).

Copyright information

© Springer-Verlag New York Inc. 1994

Authors and Affiliations

  • J. Snoeyink
    • 1
  • J. Stolfi
    • 2
  1. 1.Department of Computer ScienceUniversity of British ColumbiaVancouverCanada
  2. 2.Computer Science DepartmentUniversidade Estadual de CampinasCampinasBrazil

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