There are many ways of communicating without using speech. Signals, signs, symbols, and gestures may be found in every known culture. The basic function of a signal is to impinge upon the environment in such a way that it attracts attention, as for example, the dots and dashes of a telegraph circuit. Coded to refer to speech, the potential for communication is very great. While less adaptable to the codification of words, signs contain great meaning in and of themselves. A stop sign or a barber pole conveys meaning quickly and conveniently. Symbols are more difficult to describe than either signals or signs because of their intricate relationship with the receivers cultural perceptions. In some cultures, a audin in a theater provides performers with an auditory symbol of approval. Gestures i such as waving and handshaking also communicate certain cultural messages.