vertices = dimension1:80 dimension2:160
a = from 0 to (2*PI) dimension1
b = from (-PI*0.5) to (PI*0.5) dimension2
r = 10.0
c = sqrt(abs(a - PI))*1.5
x = r*cos(b)*sin(a)*c
y = -r*cos(b)*cos(a)*c
z = r*sin(b)*0.75

u = a
v = b*2
y = y - array_min(y)*0.5