Background: Geometry of the Dance (May 9)
and Midnight in Oslo (May 10).

Peter Pesic has described the action of the
symmetric group S4 on a tetrahedron as a dance—

IMAGE- 'The geometry of the dance' is that of a tetrahedron, according to Peter Pesic

Compare and contrast:

The following figure may be seen as a tetrahedron,
viewed from above—

IMAGE- The 'Shield of the Trinity' may be viewed as a tetrahedron, as in Peter Pesic's 'Geometry of the Dance.'

  See also Masterman and Child's Play.