A = (0, 0)
B = (6, 0)
C = (6, 9)
D = (0, 9)
poly1, a, b, c, d = Polygon(A, B, C, D)
I = Point(a)
e = Circle(C, Distance[B, I])
J = Intersect(e, b)
f = Circle(D, Distance[B, I])
K = Intersect(f, c)
g = Circle(A, Distance[B, I])
L = Intersect(g, d)
poly2, i, j, k, l = Polygon(I, J, K, L)