P1: (3, 0, 6)
P2: (6, 0, 3)
P3: (6, 3, 0)
P4: (3, 6, 0)
P5: (0, 6, 3)
P6: (0, 3, 6)
Vieleck1, p1, p2, p3, p4, p5, p6 = Polygon(P1, P2, P3, P4, P5, P6)
D1: (6, 1.5, 6)
D2: (6, 6, 1.5)
D3: (1.5, 6, 6)
d1, l, j, n = Polygon(D1, D2, D3)
E1: x + y + z = 9
E2: x + y + z = 13.5
X = PointIn(E2)
f = OrthogonalLine(X, E1)
A = Intersect(f, E1)
g = Segment(X, A)