The Tuelle surface is constituted by three smooth components, which intersect each other pairwise in a (likewise) smooth, plane curve. That way, three section curves are obtained, i.e. one straight line and two parabolas. The equation yz(x^2+y-z)=0 was suggested to use for the IMAGINARY exhibition by Herwig Hauser.
Please note: IMAGINARY is an open source and non-commercial project. All 3d files are available under an open license, such that you can re-print the sculptures for own exhibitions (following the license specifications). To reimburse our "3D data expert", who takes care to polish and prepare the 3d data and to put the sculptures on the Shapeways shop, we added to this sculpture a 10% fee to the Shapeways price. This amount will be used only for work related to offering more 3d data and sculptures openly and freely to everyone. You can also print this sculpture from your own account.