#http://www.mathcurve.com/courbes2d/cassini/cassini.shtml

vertices = D1:512 D2:100

u = from (-PI) to (PI) D1
v = from (0) to (4) D2
a = 10

p = a*sqrt(cos(2*u) + sqrt(v^4 - sin(2*u)^2))

x = p*cos(u)
y = p*sin(u)
