B = (8.059921060844601, -3.821117889205203)
D = (4.377856178680012, 3.874729432075741)
E = (4.411027934375188, -6.275827810648263)
đa giác1, c, a, b = Polygon(B, D, E)
A = Mirror(B, a)
đa giác2, c_1, b_1, a' = Polygon(D, A, E)
α = Angle(D, B, E)