Optical illusions are fascinating examples of how our brains can be tricked, revealing the complexity and occasional unreliability of human perception. Even the sharpest observers can pause and double-check what they see when confronted with clever visual tricks.

A recent viral illusion shows six girls sitting on a couch, yet only five pairs of legs appear visible. At first glance, it seems impossible—one person appears to have no legs at all. This simple image captivated social media, prompting widespread curiosity and debate.

Illusions work because our brains constantly interpret visual cues, make assumptions, and fill in missing information. According to the Queensland Brain Institute, this process is usually seamless, but clever setups exploit these shortcuts, causing the brain to misinterpret reality. Patterns, perspective, shadows, and symmetry can all be used to create these deceptive effects.