he wondered if clouds always travel in the same direction , and first decided it couldnt be so , but then figured they must at least flow the same way on the same day , since he couldnt ever remember seeing a cloud float overhead , stop , and reverse direction , and wondered if , in the history of the world , it had ever happened , but then , after considering the puzzle in those terms , changed his mind and decided it happens every time the wind blows in a different direction , which it does frequently , meaning clouds do move in one direction and then about face , even though he couldnt recall seeing it in person .