program spz;{Spiralezeichnen}
uses crt, graph;

var gd, gm, i : integer;
    s, t, e, f, durch, w : integer;

procedure spirale;
 begin
    t:=-1;
    cleardevice;
    setcolor(13);
    s:=10; t:=durch*30; e:=0; f:=0;
    for i:=1 to 400 do
       begin
         arc(round(getmaxx/2), round(getmaxy/2), s, t, i);
         s:=t; t:=t+90;
         if i=400 then
           begin
             s:=e; t:=f;
           end;
         delay(50);
       end;
    durch:=durch+1;
    delay(100);
    setcolor(13); w:=9;
  end;

begin
  gd:=9;
  gm:=2;
  initgraph(gd, gm, 'd:\tp\bgi');
  spirale;
  readln;
  closegraph;
end.