These are models of conic curves systematized by Apollonius of ancient Greece.

Using this model, it is easy to see that circles, ellipses, hyperbolas, and parabolas can be obtained from a section of a cone. A detailed introduction to each of these curves can be found on wikipedia.

If the model is too large, you may want to shrink it by 75% and print it.

Enjoy ancient Greek mathematics.

about the conic curves: [https://en.wikipedia.org/wiki/Conic_section](https://en.wikipedia.org/wiki/Conic_section)
about Applonius: [https://en.wikipedia.org/wiki/Apollonius_of_Perga](https://en.wikipedia.org/wiki/Apollonius_of_Perga)