This probably caused some headaches at shapeways, although it came out very nice in the end. I have not yet mustered the courage to inquire about the number of reprints necessary to achieve this, but I doubt that it was straightforward even though I made the connecting spheres bigger than I would have liked... The model shows a section of the crystal structure of the mineral beryl (named aquamarine or emerald as a gemstone) in the polyhedral representation commonly used in solid state chemistry where ball-and-stick models would quickly become too confusing. (The red tetrahedra each contain a silicon atom in the center, while there is an aluminum atom inside the blue octahedra and beryllium in the green polyhedra. All vertices are occupied by oxygen atoms - the red spheres.) I have left off the oxygens on the outside of the model as they would have added more weight to the more or less free-standing polyhedra and would have had a high probability of breaking off or crumbling away themselves - hopefully recent developments like the ProJet4500 will make printing similar models easier in the near future.