Mill

The $n$-roll mill curve is given by the equation

$$x^n-{n\choose 2}x^{n-2}y^2+{n\choose 4}x^{n-4}y^4-\ldots=a^n,$$

where ${n\choose k}$ is a Binomial Coefficient.

References

von Seggern, D. CRC Standard Curves and Surfaces. Boca Raton, FL: CRC Press, p. 86, 1993.