Ever wanted a elliptic paraboloid solid for OpenScad? Here it is! What is a parabolic reflector good for? Solar cookers, parabolic microphones, satellite dishes, spotlights reflector http://en.wikipedia.org/wiki/Parabolic_reflector Parabolic reflectors focus parallel rays at a focus point (e.g. sun rays). And it can make circular rays at the focus point go parallel in one direction (spotlight). It seems to be "similar" to the nose cone design of aircraft and model rockets, too. http://en.wikipedia.org/wiki/Nose_cone_design Usage : paraboloid (y=50,f=10,rfa=0,fc=0,detail=44); To create a paraboloid choose following parameters: How to print the paraboloid example: Print it with support structure for best results. Slice it with 3 perimeters, no top, no bottom, no infill. For some light experiments: You can try to cover the inner surface with a reflecting material. You can insert a stick into the small opening on top.