LinesInACircle

Draw many lines from an arbitrary point B in a circle to the circumference.  Rotate each by 90 degrees around its center. What do you notice?

https://twitter.com/3blue1brown/status/1016936129117937664

resolution

rotate them

F: (sqrt(2), 0)
E: (0, 0)
f = Segment(E, F)
B = Point(f)
reso = 0.08 (slider from 0.03 to 0.2, step 0.01)
reso_1: 0.1
A = Intersect(xAxis, yAxis)
L_1 = Sequence(Segment[(cos(k), sin(k)), B], k, 0, (2 * π), reso)
L_2 = Sequence(Midpoint[Segment[(cos(k), sin(k)), B]], k, 0, (2 * π), reso)
c = Circle(A, 1)
t = 2.57 (slider from 0 to π / 2 + 1, step 0.01)
A_1 = Min(t, π / 2)
L_4 = Sequence(Rotate[(cos(((k - 1) * reso)), sin(((k - 1) * reso))), π / 2, Midpoint[L_1(k)]], k, 1, 3)
a: π / 2 + ((2 * π)) / reso
floorA: floor(a)
L_5 = Sequence(Rotate[B, π / 2, Midpoint[L_1(k)]], k, 1, 3)
d = Circle(L_4(1), L_4(2), L_4(3))
e = Circle(L_5(1), L_5(2), L_5(3))
C, D = Intersect(d, e)
L_6 = Sequence(Line[(cos(k), sin(k)), B], k, 0, (2 * π), reso)
L_3 = Sequence(Rotate[L_1(k), Max[Min[t - (k * reso / ((2 * π))), π / 2], 0], L_2(k)], k, 1, Length[L_1])