Distorting Jessen's Orthogonal Icosahedron to an Octahedron
Jessen's icosahedron is constructed by replacing six pairs of adjacent triangles in a regular icosahedron with pairs of isosceles triangles sharing a common base. There are six bases and they form three pairs of parallel edges.[more]
This Demonstration varies the edges to distort the polyhedron until it closes up into a regular octahedron.[less]
 D. Wells, The Penguin Dictionary of Curious and Interesting Geometry, London: Penguin Books, 1991 p. 161.
"Distorting Jessen's Orthogonal Icosahedron to an Octahedron"
Wolfram Demonstrations Project
Published: January 9 2014