A pyramid with a square base is a square-based pyramid. Image caption, 3D shapes that are non-polyhedral include cylinders, cones, and spheres. At least one face is not a polygon. At least one ...

When Yukinori Kawae explores the Great Pyramids at Giza, he isn’t after treasure or lost chambers—he’s looking for dimensions. For all that the pyramids have been dug, scanned, and ...