a = 2.2 (slider from -5 to 5, step 0.1)
b = 1.9 (slider from -5 to 5, step 0.1)
c = 1.2 (slider from -5 to 5, step 0.1)
d = 1.6 (slider from -5 to 5, step 0.1)
p: a * x + b * y + c * z = d
O = (0, 0, 0)
A = (0, 0, 1)
u = Vector(O, A)
e = Cone(O, u, 0.785)
f = Intersect(p, e)
g = Intersect(q, e)
B = Point(g)