curva di Cayley , cartesiana

4 *(x^2 + y^2 - ax)^3= 27*a^2 *(x^2+y^2)^2

a = 3.5 (slider from -5 to 5, step 0.1)
b: 4 * (x^(2) + y^(2) - a * x)^(3) = 27 * a^(2) * (x^(2) + y^(2))^(2)