a = 0 (slider from 0 to 0.1, step 0.001)
u = Vector((0, 0, 0), (2, 0, 0))
b = 0 (slider from 0 to 0.1, step 0.001)
v = Vector((0, 0, 0), (0, 2, a))
w = Vector((0, 0, 0), (2, 0.1, b))
c = Plane((0, 0, 0), (0, 0, 0) + v, (0, 0, 0) + u)
d = Plane((0, 0, 0), (0, 0, 0) + u, (0, 0, 0) + w)