S = (0, 0)
C = (2, 1)
a = Segment(S, C)
A = Point(P)
b = Line(A, a)
B_1, B = Intersect(P, b)
D = Midpoint(S, C)
E = Midpoint(A, B)
d = Segment(A, E)
e = Segment(E, B)
f = Segment(S, D)
g = Segment(D, C)