柱面正弦曲线
#http://www.mathcurve.com/courbes3d/couronnetangentoidale/couronnetangentoidale.shtml vertices = 12000 t = from 0 to (20*PI) a = 10 b = rand2(1, 10) n = rand2(0.5, 10) x = a*cos(t) y = a*sin(t) z = b*cos(n*t)
