Count the number of regions made by Lissajous curve
I don't like to think too much :P
Manipulate[
{#, Composition[
# - 1 &,
Length,
Union,
Flatten,
MorphologicalComponents,
Binarize,
Rasterize
]@#} &@
ParametricPlot[{Sin[ n t], Sin[m t]}, {t, 0, 2 Pi}, Axes -> False,
PlotStyle -> Thick]
, {n, 2, 10, 1}, {m, 1, 9, 1}]
Graphics`Mesh`MeshInit[];
eps = 1/100000000;
Manipulate[Labeled[plt = ParametricPlot[{Sin[n t], Sin[(n - 1) t]}, {t, eps, 2 Pi},
Axes -> False, PlotStyle -> Thick]; plt /. Line -> Polygon,
Grid[{{"n", "p"}, {n, 2 + Length@Graphics`Mesh`FindIntersections[plt]}},
ItemStyle -> Directive[16, "Panel"]], Top], {n, 2, 10, 1}]