A. Clebsch, Diagonals on Surface, modelled by Carl Rodenberg under the direction of the famous mathematician Felix Klein. Currently portions of the collection are on display at the University of Goettingen Department of Mathematics, The University of Hong Kong Department of Mathematics, The Institute Poincare in Paris and at the Museum of Mathematics in Manhattan. http://youtu.be/YJ-53I4fX8I http://youtu.be/VeA2mi55uwE