Still searching? Slow down and examine the lower half first. Compare Grandma’s skirt and shoes, then inspect every edge and shape of the wooden chair. These puzzles trick your brain because familiar objects are often processed as complete shapes rather than collections of tiny details. Something can therefore change right before your eyes without immediately appearing unusual.

Now move back toward Grandma’s face. Her glasses are especially worth another inspection. Look carefully at both lenses, the bridge between them, and the frame surrounding her eyes. Compare one side against the corresponding side in the other picture. Ignore her smile and white hair for a moment and concentrate entirely on those glasses. The difference you’ve been searching for is much closer than you might think.