Transition
No fancy math this time. Here's what happens when you connect points on edges two apart in a regular octagon by straight lines, then let the odd-numbered vertices of the octagon go to the origin and let even-numbered vertices move away from the origin (plus various other bits of nonsense).
Code:
DynamicModule[{cols, r, u, verts},
cols = RGBColor /@ {"#35342f", "#f1f2f0"};
Manipulate[
r = 1/2 - Cos[s]/2;
u = If[s < π, s, s + 2 π];
verts =
Table[(1 - r (-1)^(If[s < π, i + 1, i])) {Cos[
2 π i/8 - u/8 - π/8],
Sin[2 π i/8 - u/8 - π/8]}, {i, 0, 7}];
Graphics[{Thickness[.005], CapForm["Round"], cols[[1]],
Table[Line[{t verts[[i]] + (1 - t) RotateRight[verts][[i]],
t RotateLeft[verts][[i]] + (1 - t) RotateLeft[verts,
2][[i]]}], {i, 1, 7, 2}, {t, 0, 1, 1/8}]}, PlotRange -> 3,
ImageSize -> 540, Background -> cols[[2]]], {s, 0., 2 π}]]