To change pen radius, first set α = 0°

show locus

Trace

show moving parts

α = 0 rad (slider from 0 to 3600°, step 5°)
s = 4.8 (slider from 0.1 to r, step 0.1)
r = 12 (slider from 0.1 to 12, step 0.1)
A = (-3.04, -0.11)
d = Circle(A, r - s)
c = Circle(A, r)
a = OrthogonalLine(A, yAxis)
B = Intersect(d, a, 1)
B' = Rotate(B, α, A)
i = Ray(A, B')
e = Circle(B', s)
C = Intersect(c, i)
b = Segment(B', C)
D = Point(b)
β: ((-(r / s)) * α)
D' = Rotate(D, β, B')
loc1 = Locus(D', α)
f = Segment(B', D')
g = false
v = false
h = true