What is an example of perceptual illusion?

An example of a perceptual illusion is the Müller-Lyer illusion, where two lines of equal length appear to be different lengths due to the orientation of arrow-like ends. One line has arrows pointing outward, making it seem longer, while the other has arrows pointing inward, making it seem shorter. This illusion demonstrates how our perception can be influenced by surrounding visual cues, leading to a misinterpretation of size. Such illusions reveal the complexities of visual processing in the brain.