# Cumulation

Cumulation

Cumulation (the dual operation to truncation) replaces the faces of a polyhedron with pyramids, such that the base of each pyramid is a face of the polyhedron and each pyramid has a height that is positive, zero, or negative. This example allows the user to experiment with cumulation of Platonic and Archimedean solids. Optionally, the user may vary the opacity of the surface of the polyhedron.