#http://www.mathcurve.com/courbes3d/spiralehyperbolique/spiralehyperbolique.shtml

vertices = 12000

t = from (-20*PI) to (20*PI)

r = 10
a = rand2(PI*0.2, PI*0.8)

x = r*cos(t)/t
z = r*sin(t)/t
y = r*cot(a)/t
