a = 3 (slider from -5 to 5, step 0.1)
b = 1.5 (slider from -5 to 5, step 0.1)
rx(t) = (cos(t) * ((a * cos(t)) + b))
ry(t) = (sin(t) * ((a * cos(t)) + b))
c = CurveCartesian(rx(t), ry(t), t, 0, 6.283185307179586)