Поворот фигуры Pascal

[Serge_Bliznykov]

ну и я старенький пример кину.
TurboPascal.

центр поворота задаётся через X0, Y0

{$N+}
uses graph,crt;
const POLYSIZE=4+1;
      STEP=0.01;
const xy:array[1..POLYSIZE]of PointType=(
(x:100;y:100),
(x:100;y:150),
(x:200;y:150),
(x:200;y:100),
(x:100;y:100));
      x0=100;
      y0=100;
var gd,gm,i:integer;
    r:array[1..POLYSIZE]of double;
    fi:array[1..POLYSIZE]of double;
    alp:double;
begin
    gd:=DETECT;
    initgraph(gd,gm,'');
    for i:=1 to POLYSIZE do
    begin
        r[i]:=sqrt(sqr(xy[i].x-x0)+sqr(xy[i].y-y0));
        if(xy[i].x-x0<>0)then fi[i]:=arctan((xy[i].y-y0)/(xy[i].x-x0))
        else if xy[i].y-y0<0 then fi[i]:=-PI/2
             else if xy[i].y-y0>0 then fi[i]:=PI/2 else fi[i]:=0;
    end;
    repeat
        for i:=1 to POLYSIZE do
        begin
            xy[i].x:=x0+round(r[i]*cos(fi[i]+alp));
            xy[i].y:=y0+round(r[i]*sin(fi[i]+alp));
        end;
        setcolor(WHITE);
        drawpoly(POLYSIZE,xy);
        delay(10);
        setcolor(BLACK);
        drawpoly(POLYSIZE,xy);
        alp:=alp+STEP;
    until keypressed;
    closegraph;
end.