9 NO119/NO125 : Marche avant/Marche arrière
Author: Frédéric Chanez

A = Point(xAxis)
c = Circle(A, 0.55)
B = Intersect(c, xAxis, 1)
C = Intersect(c, xAxis, 2)
d = Semicircle(C, B)
D = Point(d)
α = Angle(B, A, D)
e = Circle(A, 0.43)
E = Intersect(e, xAxis, 1)
F = Intersect(e, xAxis, 2)