A1 = 8.881455965917617
B1 = -10.030017680060414
A2 = -2.1785331832551385
B2 = -2.5942057662097895
A3 = 19.37907278547142
B3 = 12.964762019914627
A4 = 9.375661952552454
B4 = 16.248107540316195
A: (A1, B1)
B: (A2, B2)
C: (A3, B3)
D: (A4, B4)
pts: {A, B, C, D}
a = FitLineY(pts)
f = FitPoly(pts, 2)
b = CurveCartesian(A1, t, t, B1, f(A1))
c = CurveCartesian(A1, t, t, f(A1), B1)
E = Point(f)