Rukkilill

k = 20 (slider from 0 to 20, step 0.01)
a = CurveCartesian((sin((k * θ)) + 1; θ), θ, 0, (2 * π))
b = CurveCartesian((sin((k * θ)) + 2; θ), θ, 0, (2 * π))
c = CurveCartesian((sin((k * θ)); θ), θ, 0, (2 * π))
d = CurveCartesian((cos((k * θ)); θ), θ, 0, (2 * π))