Flexible Polyhedron
date: label: date made
content: 1985
name: label: maker
content: Connelly, Robert
notes: label: Description
content: The mathematician Leonard Euler once wrote,"A closed spatial figure allows no changes, as long as it is not ripped apart." Proving the "rigidity" of polyhedra was another matter. In 1813, Augustin-Louis Cauchy showed that a convex polyhedral surface is rigid if its flat polygonal faces are held rigid. In 1974, Herman Gluck proved that almost all triangulated spherical surfaces were rigid. However, in 1977 Robert Connelly of Cornell University found a counterexample, that is to say a flexible polyhedron. He built this model of such a surface some years later. It is made of cardboard and held together with duct tape. Two cutout plastic windows allow the viewer to observe changes when the polyhedron is flexed. The top section has 12 large faces and a six-faced appendage. The bottom section has 12 corresponding faces but no appendage.
label: Location
content: Currently not on view
place: label: Place Made
content: United States: New York, Ithaca
topic: label: Subject
content: Mathematics
setName: label: See more items in
content: Medicine and Science: Mathematics
label: See more items in
content: Science & Mathematics
creditLine: label: Credit Line
content: Prof. Robert Connelly
dataSource: label: Data Source
content: National Museum of American History
identifier: label: ID Number
content: 1990.0492.01
label: accession number
content: 1990.0492
label: catalog number
content: 1990.0492.01
objectType: label: Object Name
content: geometric model
physicalDescription: label: Physical Description
content: plastic (overall material)
label: Physical Description
content: paper (overall material)
label: Measurements
content: overall: 14 cm x 47 cm x 25.5 cm; 5 1/2 in x 18 1/2 in x 10 1/16 in