\text{ Kocka }ABCDEFGH:A(-4,4,-2),B(4,-4,-2)

d = 8 (slider from 5 to 8, step 0.2)
A: (-4, -4, -2)
k = Circle(zAxis, A)
O': (0, 0, d - 2)
O: (0, 0, -2)
u = Line(A, O)
q_{1} = Plane(zAxis, u)
q = OrthogonalLine(O, q_{1})
D, B = Intersect(q, k)
C, E = Intersect(u, k)
q1, a_1, b_{1}, c, d_{2} = Polygon(A, B, C, D)
p = OrthogonalPlane(O, zAxis)