Ponzo Illusion
This geometric optical illusion from the early 1900s is called the Ponzo illusion – named after Mario Ponzo, who was the first to demonstrate this effect.
The illusion uses linear perspective to confuse the brain into thinking that two lines are of different lengths. In the image below, the red line at the top of the figure appears to be longer than the red line at the bottom.
This phenomenon is still used by optical illusion artists today to trick the eye and deceive the mind.