Octahedra Constructed from Eight Identical Triangles
Eight identical copies of any triangle can be used to construct an octahedron, known as the 4-scalenohedron. Choose an arbitrary integer-sided triangle and the Demonstration builds an octahedron using eight copies of . There are as many as three possible solutions for every set of three sides. Some scalenohedra have rational volumes.
 Wikipedia. "Bipyramid." (Aug 13, 2015) en.wikipedia.org/wiki/Bipyramid.