ARIATIONS OF CONCAVE PYRAMIDS OF SECOND SORT WITH AN EVEN NUMBER OF BASE SIDES
Concave pyramids of second sort (CP II) are formed similarly to concave cupolae of second sort (CC Dishwasher Plate Tray II) with a comparable logic of emergence to the regular-faced convex pyramids.They are formed by enclosing the space over a regular polygonal base by the lateral deltahedral wrapper consisting of equilateral triangles meeting in