D = (-2.08, 1.6)
a = 1 (slider from -5 to 5)
C = Point(Circle[D, (2 * a)])
f = Segment(D, C)
g = OrthogonalLine(D, f)
h = 1.4 (slider from -5 to 5)
c = Circle(D, h)
C_1, A = Intersect(c, g)
i = OrthogonalLine(A, g)
d = Circle(A, a)
B, F = Intersect(d, i)
j = Segment(B, C)
q1, d_1, e, b, a_1 = Polygon(A, B, C, D)
k = Segment(A, C)
l = Segment(B, D)
G = Intersect(k, l)
α = Angle(B, G, A)