Мигание звезд на ночном небе

uses graphABC;
begin
clearwindow(clblack);
setbrushcolor(clyellow);
circle (10,100,4);
circle (100,100,4);
circle (232,230,5);
circle (600,230,4);
circle (300,200,4);
circle (100,100,6);
circle (30,10,4);
circle (123,150,4);
circle (600,160,5);
circle (700,10,5);
circle (553,150,6);
circle (400,120,5);
circle (300,140,5);
circle (500,150,4);
circle (450,180,4);
circle (700,170,4);
circle (503,124,4);
circle (300,30,4);
circle (200,10,6);
circle (321,160,4);
circle (150,10,5);
circle (223,150,6);
circle (10,243,5);
circle (23,180,6);
end.

uses crt,graphABC;
var i: byte;
begin
repeat
clearwindow(clblack);
if i=0 then setbrushcolor(clyellow)
   else setbrushcolor(clblack);
if i=0 then i:=1 else i:=0;
circle (10,100,4);
circle (100,100,4);
circle (232,230,5);
circle (600,230,4);
circle (300,200,4);
circle (100,100,6);
if i=0 then setbrushcolor(clyellow)
   else setbrushcolor(clblack);
if i=0 then i:=1 else i:=0;
circle (30,10,4);
circle (123,150,4);
circle (600,160,5);
circle (700,10,5);
circle (553,150,6);
circle (400,120,5);
circle (300,140,5);
if i=0 then setbrushcolor(clyellow)
   else setbrushcolor(clblack);
if i=0 then i:=1 else i:=0;
circle (500,150,4);
circle (450,180,4);
circle (700,170,4);
circle (503,124,4);
circle (300,30,4);
circle (200,10,6);
circle (321,160,4);
if i=0 then setbrushcolor(clyellow)
   else setbrushcolor(clblack);
if i=0 then i:=1 else i:=0;
circle (150,10,5);
circle (223,150,6);
circle (10,243,5);
circle (23,180,6);
if i=0 then setbrushcolor(clyellow)
   else setbrushcolor(clblack);
if i=0 then i:=1 else i:=0;
sleep(50);
redraw;
until keypressed;
end.