I think there is a problem with a number of primitive types in GeometryTypes. For example, Quad is supposed to stand for quadrilateral, but can only represent parallelograms in 3D space, and the help says it is a rectangle in 3D space!!! That is some severe inconsistency.
help?> Quad
search: Quad quadgk GLQuad quantile quantile! isequal sequential_palette
A rectangle in 3D space.