Once you have examined the man, turn your attention to the red fire hydrant and the sidewalk. Compare the outlines, individual sections, and positions of the objects shown in both pictures. Dividing the scene into smaller areas can make the search easier to organize. You might check the upper section first, then the middle, and finally the lower portion, keeping track of the areas you have already reviewed. This is a recreational observation puzzle, so there is no need to treat the result as a measure of intelligence or ability. It simply offers an opportunity to pause, concentrate, and enjoy a visual challenge.
For your final attempt, move steadily from the man’s hair down to his clothing, hands, and watch, then finish with the hydrant and surrounding pavement. Avoid dismissing a feature just because it looked familiar during your earlier search. Compare it directly with its counterpart and check whether its shape, position, and outline match. If you have already spotted the difference, look once more to confirm your choice. If you are still searching, take a brief break before returning with fresh attention. Which single detail separates these two otherwise matching illustrations of the man checking his watch?