An autostereogram is a type of optical illusion that allows viewers to see a three-dimensional image hidden within a two-dimensional pattern. By focusing their eyes in a specific way, individuals can perceive depth and shapes that are not immediately visible. This technique relies on the brain's ability to interpret visual information from slightly different angles. These images often consist of repeating patterns or textures, which can be created using computer software. Popularized in the 1990s, autostereograms are sometimes referred to as Magic Eye images, named after a popular series of books that featured them. They provide a fun and engaging way to explore visual perception.