Example 6 - Caustics in a Cup of Coffee

Example 6 - Caustics in a Cup of Coffee

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The Nephroid curve generated by reflecting a set of parallel rays in a circle, and then taking the envelope of the reflected rays.

(An envelope is created in Geometry Expressions as the locus of a line or line segment).

 

This curve is the caustic which youd observe if you shone a light obliquely into a cup of coffee.