Uses CRT, GraphABC;
Var d,m,x,y:integer;
xx,yy,t,a:real; n,k:integer;
Const
xo=320; yo=240;
Begin
  a:=0;
  for n:=1 to 20 do begin
    t:=0;
    for k:=1 to 6280 do begin
      xx:=200*cos(t);
      yy:=80*sin(t);
      x:=round(xo+(xx*cos(a)-yy*sin(a)));
      y:=round(yo-(xx*sin(a)+yy*cos(a)));
      PutPixel(x,y,white);
      t:=t+0.001;
    end;
    a:=a+pi/20;
  end;
End.