t = 1.9168146928204144 (slider from -6.283185307179586 to 12.566370614359172, step 0.1)
M: (t, 1)
c = Circle(M, 1)
a = OrthogonalLine(M, xAxis)
A = Intersect(a, xAxis)
d = Segment(M, A)
P = Rotate(A, -t, M)
α = Angle(P, M, A)
b = Segment(P, M)