RHODONEA CURVES

Rose curves r = cos(k·θ) — named by Guido Grandi 1723. Petal count depends on k in surprising ways.

r = cos(k·θ): if k is odd → k petals; if k is even → 2k petals; if k = n/d (rational) → n·d or 2n·d petals (depending on parity).