The term illusion refers to a specific form of sensory distortion. Unlike a hallucination, which is a distortion in the absence of a stimulus, an illusion describes a misinterpretation of a true sensation. For example, hearing voices regardless of the environment would be a hallucination, whereas hearing voices in the sound of running water (or other auditory source) would be an illusion.
Mimes are known for a repertoire of illusions that are created by physical means. The mime artist creates an illusion of acting upon or being acted upon by an unseen object. These illusions exploit the audience's assumptions about the physical world. Well known examples include "walls", "climbing stairs", "leaning", "descending ladders", "pulling and pushing" etc.