For example, the light rays reflected from a parabola's focus do not intersect, therefore its envelope do not form any curve. Another example is illustrated by the catacaustic of an astroid . Formulas Properties Catacaustic and Diacaustic with parallel rays Catacaustic of a curve C with parallel rays from one direction generate a curve that is also the diacaustic of the curve C with parallel rays from the opposite direction. Catacaustic and diacaustic of sinusoid . Catacaustic and diacaustic of an ellipse .
Many special curves are the caustic of other special curves.
See the table at Curve Family Index . Related Web Sites see Generic Reference Page . MacTutor Famous Curve Index . Henrik Wann Jensen. Some computer simulated images of caustics.