woahdude

Our brain first assumes that the light comes from above that's why it assumes here that the light comes from top left. Then the plates look like upside down. As soon as it finds indications that the bowls are upright and the light comes from bottom right all the bowls look upright. The most left and most right bowls look kind of warped or not flat on the table assumed that they are upside down. The shadow in the middle also gives away that the bowls are not upside down.