t = 2.69 (slider from 0 to 6.283185307179586, step 0.01)
f_x = 1 (slider from 1 to 10, step 1)
f_y = 1 (slider from 1 to 10, step 1)
P: 3.0 * (cos(f_x * t), sin(f_y * t))
Q: (3.0 * cos(f_x * t), -(3.0))
R: (-(3.0), 3.0 * sin(f_y * t))
a = Segment(P, Q)
b = Segment(P, R)
c = Segment((-3.0, -3.0), (-3.0, 3.0))
d = Segment((-3.0, -3.0), (3.0, -3.0))