spiriche di Perseo

cartesiana

(x^2 + y^2)^2 = k * x^2 + h*y^2 + w

k = -5 (slider from -5 to 5, step 0.1)
h = 5 (slider from -5 to 5, step 0.1)
w = 0.1 (slider from -5 to 5, step 0.1)
a: (x^(2) + y^(2))^(2) = k * x^(2) + h * y^(2) + w