Hopf fibration
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In differential topology, the Hopf fibration describes a 3-sphere in terms of circles and an ordinary sphere. Discovered by Heinz Hopf in 1931, it is an influential early example of a fiber bundle. Te
Pairwise linked keyrings mimic part of the Hopf fibration.
Grand antiprism
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In geometry, the grand antiprism or pentagonal double antiprismoid is a uniform 4-polytope bounded by 320 cells: 20 pentagonal antiprisms, and 300 tetrahedra. It is an anomalous, non-Wythoffian unifor
100 tetrahedra in a 10×10 array forming the Clifford torus boundary in the 600-cell and grand antiprism.