Illusions are perceptions that differ from reality, often tricking our senses into seeing or experiencing something that isn't there. They can occur in various forms, such as visual, auditory, or tactile illusions. For example, a mirage on a hot road may appear as water, but it is actually just light refracting through hot air. Illusions are often used in art and entertainment to create surprising effects. Famous examples include the works of M.C. Escher, who created intricate designs that challenge our understanding of space and perspective. Understanding illusions can help us learn more about how our brains process information and interpret the world around us.