var i,x,y;

procedure draw;
begin
  call cvclear;
  call cvball(x,y,10);
  call cvline(cvx,cvy,x,y);
  call wait(10)
end;

begin
i:=0;
while 1=1 do
  begin
    call cvclear;
    call cvclick;
    i:=i+1;
    out:=i;
    x:=cvx;
    y:=cvy;
    while cvx>-1 do
      call draw
  end
end.