\text{Rovnobežnosten 

a = 4 (slider from 2 to 6, step 0.5)
α = 0.7853981633974483 rad (slider from 30° to 60°, step 0.017453292519943295)
k_{2} = 3 (slider from 1 to 5, step 1 / 3)
k: k_{2} / 6
text9 = FractionText(k)
A = (4, 2)
B = Point(Circle[A, a])
A' = (2.1652398945121676, 7.028766131851936)
f = Segment(A, B)
k_{1} = Line(A, B)
text1: "1.  \; \left| AB \right| =a=" + (LaTeX[a]) + ""
A'_{1} = Rotate(A, (-(180° - α)), B)
g = Line(B, A'_{1})
β = Angle(k_{1}, g)
E = (10.052272492786985, -0.3643310915814364)
c = Circle(B, (k * a))
C = Intersect(c, g, 2)
h = Line(A, g)
i = Line(C, f)
D = Intersect(h, i)
j = Segment(A, A')
l = Line(A', g)
m = Line(A', k_{1})
n = Line(B, j)
B' = Intersect(m, n)
p = Segment(A', B')
q = Segment(B', B)
r = Line(C, n)
s = Line(B', h)
C' = Intersect(r, s)
t = Segment(B', C')
b = Segment(C', C)
d = Segment(C, B)
e = Line(C', m)
D' = Intersect(l, e)
f_1 = Segment(A', D')
g_1 = Segment(D', C')
h_1 = Segment(A, D)
i_1 = Segment(D, C)
j_1 = Segment(D, D')