the ink moves away in the opposite direction to the ballpoint so that there's a gap between the ink inside the pen and the ballpoint. You put a pen in your pocket, take it out later to find that it isn't working because the ink has flowed up the pen in the opposite direction to the ballpoint. Why does this happen? It is too extreme to be just gravity when there's a huge gap between ink and ballpoint in the pen and the pen's only been in your pocket about an hour, right?