T174

a = Surface(cos(s), sin(s), t, s, 0, (2 * pi), t, 0, 1)
b = Surface((t * cos(s)), (t * sin(s)), 0, s, 0, (2 * pi), t, 0, 1)
c = Surface((t * cos(s)), (t * sin(s)), t, s, 0, (2 * pi), t, 0, 1)
d = Surface((cos(s) * cos(t)), (cos(s) * sin(t)), sin(s), s, 0, pi / 2, t, 0, (2 * pi))
p = 0.5 (slider from -5 to 5)
q: z = p