intothecontinuum:

A Moiré pattern formed with 2 sets of rays.

Code for Mathematica:

Manipulate[
 Graphics[
  {Thickness[.005],
   {Blue, {Line[
      Table[{{Cos[t], Sin[t]}, {0, 0}}, {t, 2. Pi/150, 2. Pi, 2. Pi/150}]]}},
   {Line[Table[{{Cos[t], Sin[t]}, {0, s}}, {t, 2. Pi/150, 2. Pi, 2. Pi/150}]]}}, 
  PlotRange -> 1],
 {s, .5, -.5, .1}]