

One of the eight convex deltahedra built up from 16 equilateral triangles. It consists of two oppositely faced square pyramids rotated to each other and separated by a 4antiprism. It is Johnson solid .
If the centroid is at the origin and the sides are of unit length, the equations of the 4antiprism give height of the middle points as . Adding the height of the square pyramids gives apex heights of . The surface area and volume of the solid are
(1)
 
(2)
 
(3)
