uses graph, crt;
var d, m, x: integer;
begin
 d:=vga; m:=vgamed;
 initgraph(d, m, '');
 x:=100;
 repeat
   cleardevice;
   line(x, 50, x, 200);
   delay(30);
   x:=x+2;
 until x>200;
 closegraph;
end.