A = (4, -1)
B = (5, 4)
C = (-1, 3)
a = Segment(A, B)
b = Segment(A, C)
c = Segment(B, C)
ha = OrthogonalLine(A, c)
hb = OrthogonalLine(B, b)
hc = OrthogonalLine(C, a)
H = Intersect(hc, hb)