f(x) = If[0 ≤ x ≤ 4, 1, If[x > 4, 2]]
A = (-0.0004479273235586289, -0.5314562571162609)
B = (5, 0)
h = Line(A, xAxis)
g = Line(B, yAxis)
P: (4, 2)
Q: (4, 1)