x0=0;
y0=0;

polomer=1;

amin=-0.5;
amax=0.5;
deltaa=0.1;
a0=0;

xmin=x0-1.1(polomer+amax);
xmax=x0+1.1(polomer+amax);
ymin=x0-1.1(polomer+amax);
ymax=x0+1.1(polomer+amax);

pocet=30;
fi=(π/2);

barva=Black;
barvakce=Black;
velikostbodu=0.025;
velikostpisma=18;

Manipulate[
If[smer=="horizontální",
body=Table[
Point[{x0+(polomer+a) Cos[((2π)/pocet)i],y0+(polomer-a) Sin[((2π)/pocet)i]}],
{i,1,pocet,1}],
body=Table[
Point[{(x0+(polomer+a) Cos[((2π)/pocet)i]) Cos[fi]-(y0+(polomer-a) Sin[((2π)/pocet)i])Sin[fi]+(polomer+a) Cos[((2π)/pocet)i],(x0+(polomer+a) Cos[((2π)/pocet)i]) Sin[fi]+(y0+(polomer-a) Sin[((2π)/pocet)i]) Cos[fi]+(polomer-a) Sin[((2π)/pocet)i]}],
{i,1,pocet,1}]];

Graphics[{
{barvakce,PointSize[velikostbodu],body}
},
FormatType->StandardForm,
AspectRatio->Automatic,
PlotRange->{{xmin,xmax},{ymin,ymax}},
ImageSize->600
],

{{a,a0,Style["a",velikostpisma,barva]},amin,amax,deltaa},
{{smer,"horizontální",Style["směr polarizace",velikostpisma,barva]},{"horizontální","šikmá"}},
FrameLabel->{Style["© Jaroslav Reichl, 2016",10,Black,FontFamily->Times],"",Style["Gravitační vlny - ukázka polarizace",25,Black,FontFamily->Times],""}]