A Moiré pattern formed with 5 sets of concentric circles.

Code for Mathematica:Manipulate[

Graphics[

{Thickness[.005],

{Table[Circle[{0, 0}, r], {r, 0, 1, .05}],

Table[Circle[{2 t, 0}, r], {r, 0, 1, .05}],

Table[Circle[{-2 t, 0}, r], {r, 0, 1, .05}],

Table[Circle[{0, 2 t}, r], {r, 0, 1, .05}],

Table[Circle[{0, -2 t}, r], {r, 0, 1, .05}]}}],

{t, 0, 1, .05}]