And those polar field lines some think are straight are not straight at all.
They eventually curve to the opposite pole.
The reason most iron-filing set-ups appear to show a polar straight line is that the magnetic force at that point is too weak to align the relatively massive iron-filings into a curve.
Well I tried it. I took a 300mm Iron rod and a N42 nib magnet, starting in the center of the rod and switching to the other side, again starting from the center after each stroke. I then brought it proximity to a compass and indeed the north end of the needle pointed to the end of either side of the rod. I also noticed that the south end of the needle pointed to the center of the rod as I was passing it. So, what you have is not a monopole it just has the same pole on each end and the opposite pole in the middle.
about 2nd solution, when you conected to magneteic with north-north, and South - south , infact, you have one magnetic which is weaker than both of first mgnetic because, their magnetic fields destroy each other...