A = (0, 0)
B = (5, 0)
a = Segment(A, B)
Leiter = Point(a)
r = Segment(Leiter, B)
b = OrthogonalLine(B, a)
u = UnitVector(b)
resi = 4.5
O: B + (resi + 1) u
d = Segment(B, O)
Fenster: B + resi u
leiter = 5
F: (5, sqrt(25 - r²))
h = Segment(B, F)
s = Segment(Leiter, F)