Abstract: Apparatus for constructing a pyramid. The apparatus comprises a circular piece of material having a circular front face; a circular back face; and a plurality of fold lines formed on at least one of the faces. The fold lines include diameter lines each traversing and passing through the center point of the circular face, and chord lines each shorter in length than the diameter lines, either end of the chord lines and the diameters lines coinciding with a point on the circumference of the face. The pyramid is formed by sequentially folding the circular piece of material along the fold lines.