diff = 6 (slider from 0 to 8, step 0.1)
A = Point(xAxis)
B: -(A)
D = Point(Circle[B, diff])
a = Segment(B, D)
b = Segment(A, D)
c = LineBisector(b)
E = Point(c)
poly1, e, a_1, d = Polygon(A, D, E)