The unscripted nature of improv also implies no predetermined knowledge about the props that might be useful in a scene. Improv companies may have at their disposal some number of readily accessible props that can be called upon at a moment's notice, but many improvisers eschew props in favor of the infinite possibilities available through mime. In improv, this is more commonly known as 'space object work' or 'space work', rather than 'mime', and the props and locations created by this technique, as 'space objects' created out of 'space substance', developed as a technique by Viola Spolin. As with all improv 'offers', improvisers are encouraged to respect the validity and continuity of the imaginary environment defined by themselves and their fellow performers; this means, for example, taking care not to walk through the table or "miraculously" survive multiple bullet wounds from another improviser's gun.
