k = 4.441 (slider from 0 to 8, step 0.001)
A = Point(yAxis)
B = Point(zAxis)
C: (4, 0, 8)
O = Intersect(xAxis, zAxis)
t1, a, d, b = Polygon(O, B, A)
c, faceBCD, faceABC, faceACD, arêteCD, arêteBC, arêteAC = Pyramid(t1, C)
f = Segment(O, B)
M: (0, 0, k)
p = OrthogonalPlane(M, f)
N = Intersect(arêteCD, p)
P = Intersect(arêteAC, p)
Q = Intersect(d, p)
q1, e, f_1, g, h = Polygon(M, N, P, Q)
i = Segment(M, P)
α = Angle(M, P, C)
j = Segment(O, B)