deltoid, caustics, pov-ray,conic sections

a POV-Ray generated shadow of sphere.

http://xahlee.org/SpecialPlaneCurves_dir/ConicSections_dir/ball_shadow.png

(must go to the html page below to access)

http://xahlee.org/SpecialPlaneCurves_dir/ConicSections_dir/conicSections.html

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Caustics of Deltoid curve by parallel rays

http://xahlee.org/SpecialPlaneCurves_dir/ggb/deltoid_caustics.html