b

b

a

a

b

A = (0.28, 0.98)
B = (3.38, 1.54)
f = Line(A, B)
C = (2.56, -0.88)
g = Line(B, C)
h = Line(C, f)
i = Line(A, g)
D = Intersect(h, i)
α = Angle(A, B, C)
δ = Angle(C, D, A)
a = 2 (slider from 0 to 5, step 1)
j = Segment(A, B)
k = Segment(D, C)
l = Segment(A, D)
m = Segment(B, C)
ε = Angle(D, A, B)
ζ = Angle(B, C, D)
H = Point(f)
θ = Angle(H, A, D)