This is a sinusoid plotted in polar coordinates, given by *r =
cos(kθ)* for some fixed *k*.

If *k = p/q* is rational with *p* and *q* relatively
prime, then the curve has period *πq* when *p* and *q* are
both odd, otherwise *2πq*. If *k* is irrational, then it will
have infinitely many petals.

- Rose (mathematics) on Wikipedia.
- Rose on MathWorld.

© Jason Davies 2012.