IIIF provides researchers rich metadata and media viewing options for comparison of works across cultural heritage collections. Visit the IIIF page to learn more. This wooden model shows a triangular ...

During a recent house sale, a 4½-inch-high heavy glass pyramid was for sale. The item was inexpensive, but no one knew what it was used for. It was almost too heavy to lift, so it wouldn't be a ...

A pyramidal prism/angular cube reflector is always used to reflect a beam of light into the prism, regardless of the direction of the beam. Corner prisms are widely used where accurate alignment is ...

George Wentworth with David E. Smith,, Plane and Solid Geometry, Boston: Ginn and Company, 1906, p. 342 .