A rose-like curve whose radius is modulated by cos((a/b)·t), tracing one petal per integer period of the frequency ratio.
cos((a/b)·t)
x(t) = radius·cos((a/b)·t)·cos(t)y(t) = radius·cos((a/b)·t)·sin(t)
x(t) = radius·cos((a/b)·t)·cos(t)
y(t) = radius·cos((a/b)·t)·sin(t)