uses graph;

Type
   Sides=record
      x1,y1,x2,y2:real;
   end;

var
   grDriver, grMode, ErrCode: Integer;
   Stars:array[1..20] of Sides;
   i,j:integer;
   R:real;
   n:integer;
   x0,y0:real;

{***********************************************************************}

Procedure Star(n:integer;x0,y0:real;R:real;var Stars:array of Sides);

Var
   R0:real;
   bufx,bufy:real;

begin

R0:=R;
R:=3*R;

for i:= 1 to n do
begin
Stars[i].x1:= x0+Trunc(R*Sin(i*2*Pi/n));
Stars[i].y1:= y0+Trunc(R*Cos(i*2*Pi/n));
Stars[i].x2:=x0+Trunc(R0*Sin(i*2*Pi/n));
Stars[i].y2:=y0+Trunc(R0*Cos(i*2*Pi/n));
end;

bufx:=Stars[1].x2;
bufy:=Stars[1].y2;

for i:=1 to n do
begin
if i=n then
   begin
   Stars[i].x2:=Stars[i].x2+((bufx-Stars[i].x2)/ 2);
   Stars[i].y2:=Stars[i].y2+((bufy-Stars[i].y2)/ 2);
   end
else
   begin
   Stars[i].x2:=Stars[i].x2+((Stars[i+1].x2-Stars[i].x2)/ 2);
   Stars[i].y2:=Stars[i].y2+((Stars[i+1].y2-Stars[i].y2)/ 2);
   end;
end;

end;

{***********************************************************************}

Procedure DrawStar(n:integer;Stars:array of Sides);

begin

for i:=1 to n do
begin
if i=n then
   begin
   line(Trunc(Stars[i].x1),Trunc(Stars[i].y1),Trunc(Stars[i].x2),Trunc(Stars[i].y2));
   line(Trunc(Stars[i].x2),Trunc(Stars[i].y2),Trunc(Stars[1].x1),Trunc(Stars[1].y1));
   end
else
   begin
   line(Trunc(Stars[i].x1),Trunc(Stars[i].y1),Trunc(Stars[i].x2),Trunc(Stars[i].y2));
   line(Trunc(Stars[i].x2),Trunc(Stars[i].y2),Trunc(Stars[i+1].x1),Trunc(Stars[i+1].y1));
   end;
end;

end;

{***********************************************************************}

begin

  grDriver := Detect;
  InitGraph(grDriver, grMode, '');
  ErrCode := GraphResult;
  if ErrCode <> grOk then
  begin
    Writeln('Graphics error:', GraphErrorMsg(ErrCode)); halt(100)
  end;

n:=3;
x0:=325;
y0:=225;
R:=40;

Star(n,x0,y0,R,Stars);
DrawStar(n,Stars);

readln;

end.