vertices = D1:360 D2:72
u = from 0 to (5*PI) D1
v = from 0 to (4*PI) D2

a = 5
h = rand2(5, 20)

x = a*sh(u - v)*cos(u+v)
y = h*(u + v)
z = a*sh(u - v)*sin(u+v)

w = 50
x = limit(x, -w, w)
z = limit(z, -w, w)