Forgive the sloppy use of math and inability to produce an image. I noticed this last christmas.(adsbygoogle = window.adsbygoogle || []).push({});

If you have a fairy light ( or perhaps any LED etc), and shine it normal to a surface, you see a circle. If you place the light flat on the surface you see a curve - to me the fairy lights' curve looks like a hyperbola.

Does this have any relation to the equation of a circle:

[tex]x^2+y^2=const.[/tex]

And Hyperbola:

[tex]x^2-y^2=const.[/tex]

And subsitution for 90 degrees rotation? :

[tex]y\rightarrow iy[/tex]

If so, how does this even work? The experiment is all in real space. If not, is this just sloppy use of math? Any significance?

Thanks

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# Christmas tree light

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