Reflection twice
Author: R. Albers

Take the point E and move it to the left.
Line d and e are connected by a fixed angle α, so e moves as well as d.

Double click opens the workfile for measurement and construction.

Der Winkel α ist fest. Bewegen Sie den Punkt E nach links.
Damit verändert sich wieder die Achse DE, aber gleichzeitig auch die Achse DF.
In welche Richtung wird sich das grüne Dreieck bewegen?

A = (8.5, -3.74)
B = (10.42, -2.5800000000000027)
C = (9.52, 0.6799999999999999)
poly1, c, a, b = Polygon(A, B, C)
D = (4.24, -5.96)
E = (9.52, 2.22)
d = Line(D, E)
A' = Mirror(A, d)
B' = Mirror(B, d)
C' = Mirror(C, d)
poly1', c', a', b' = Polygon(A', B', C')
F = Rotate(E, 40*°, D)
α = Angle(E, D, F)
e = Line(D, F)
A'' = Mirror(A', e)
B'' = Mirror(B', e)
C'' = Mirror(C', e)
poly1'', c'', a'', b'' = Polygon(A'', B'', C'')