Author: Daniel Mentrard

C = (-1.9962810868676308, 7.441999396406092)
B = (-5.024807132463228, -7.410224224459987)
I = (14, 0)
D_1 = (6, 0)
z = Vector(C, D_1)
w = Vector(B, D_1)
D = (-21.20460381441231, 8.811059115647938)
i = Vector(D, D_1)
Ver = 0 (slider from 0 to 3, step 0.2)
t: (1.0 + sgn(3.0 - Ver)) / 2.0
u: (1.0 + sgn(2.0 - Ver)) / 2.0
k: (1.0 + sgn(1.0 - Ver)) / 2.0
a_1: k * u * t
a_4: (1.0 - k) * (1.0 - u) * (1.0 - t)
a_3: (1.0 - k) * (1.0 - u) * t
b_3: a_3 * (Ver - 2.0) + a_4
A''': D + z * b_3
B''': B + z * b_3
C''': C + z * b_3
a_2: (1.0 - k) * u * t
b_2: a_2 * (Ver - 1.0) + a_3 + a_4
C'': C + w * b_2
B'': B + w * b_2
b_1: a_1 * Ver + a_2 + a_3 + a_4
K: D + i * b_1
S: C + i * b_1
Ψ = Angle(S, D_1, I)
M = Rotate(S, Ψ * b_1, K)
A = (-20.748250574665025, -7.783604147889581)
A'': A + w * b_2
v = Vector(A, D_1)
C': D + v * b_1
A': A + v * b_1
B': B + v * b_1
ζ = Angle(B', D_1, I)
L = Rotate(C', ζ * b_1, A')
δ = Angle(L, D_1, C'')
E = Rotate(C'', -(δ) * b_2, B'')
F = Rotate(A'', -(δ) * b_2, B'')
β = Angle(E, B'', F)
ε = Angle(F, D_1, A''')
G = Rotate(A''', -(ε) * b_3, C''')
H = Rotate(B''', -(ε) * b_3, C''')
θ = Angle(G, C''', H)
J = Rotate(B', ζ * b_1, A')
α = Angle(J, A', L)
T: A + i * b_1
R = Rotate(T, Ψ * b_1, K)
γ = Angle(R, K, M)
O = Midpoint(D_1, I)
P = Mirror(O, D_1)
η = Angle(A, D_1, B)
poly1, a, b, c, d_1 = Polygon(A, B, C, D)
α_1 = Angle(B, A, C)
β_1 = Angle(C, B, A)
γ_1 = Angle(A, C, B)
d = Ray(D_1, I)
poly2, e_1, f_1, g_1, h = Polygon(C, B, A, D)
e = Line(D_1, xAxis)
f = Circle(D_1, I)
g = Segment(P, O)
N = Point(g)
Q = Point(g)
r = Segment(A, B')
U = (3.438471131940906, 2.339140442868305)
T2: "α + β + θ + Ψ = " + α + " + " + β + " + " + θ + " +" + γ + "= " + (α + β + θ + γ)
p = Circle(D_1, 3.5)